Fire Blogs

Costliest (and Deadliest?) Disaster of 2015: Indonesia's $14 Billion Fires

By Dr. Jeff Masters
Published: October 13, 2015
Earth's most expensive weather-related disaster of 2015--and the most expensive disaster in Indonesia's history--is underway in that nation, where massive clouds of smoke from agricultural fires have choked the lungs of tens of millions of people for months. Indonesia's Center for International Forestry Research estimated the smoke will cost $14 billion in agriculture production, forest degradation, health, transportation and tourism, according to an October 9 article in The Wall Street Journal. Indonesia's Health Ministry says 20 million people--8% of the country's population--have been impacted by this year's haze; 120,000 of them have sought medical attention for respiratory problems. The disaster may also be the deadliest disaster of 2015, depending upon how one treats the difficult task of determining air pollution deaths. Over 10,000 adults are likely to die from pollution from the fires, judging by the results of a 2013 study in Nature Climate Change by Marlier et al., El Niño and health risks from landscape fire emissions in Southeast Asia. The researchers found that during the strong El Niño year of 1997, the extra smoke in the air in Southeast Asia likely caused an additional 10,800 adult deaths due to cardiovascular disease, and the fires of 2015 are putting a comparable amount of smoke into the air. (Globally, pollution due to fires between 1997 - 2006 was estimated to kill 532,000 people during an average El Niño year--about double the estimated 262,000 deaths that occurred in La Niña years.) Haze from this year's fires is also seriously impacting Malaysia, Singapore, Vietnam and Thailand. The haze in Singapore was so bad that it forced the cancellation of a "zombie apocalypse" competition last month.

Figure 1. Buildings (background) along Shenton way business district are blanketed with thick smog in Singapore on September 24, 2015. Singapore's air quality reached 'very unhealthy' levels on September 24, forcing schools to close, as thick smog from agricultural fires in Indonesia's neighboring Sumatra Island choked the city-state. Image credit: ROSLAN RAHMAN/AFP/Getty Images.

Figure 2. MODIS image of smoke from fires burning in southern Sumatra and Borneo in Indonesia as seen from NASA's Terra satellite at 03:15 UTC September 24, 2015. The red squares are fires detected from the spacecraft. Image credit: NASA.

The culprit: El Niño-driven drought
The warm waters off the Pacific coast of Peru during a strong El Niño episode generate a column of rising air over the tropical Eastern Pacific. Once this rising air reaches the bottom of the stratosphere, which acts as a stable lid preventing further rising motion, the warm air is forced to spread out to the east and west along the Equator. This air eventually sinks over tropical regions well to the east and the west of the Eastern Pacific to complete a huge circulation cell several thousand miles in diameter. Since sinking air warms and dries as it descends, areas of high pressure and drought tend to form in these sinking air regions. To the west of the Eastern Pacific, El Niño events tend to create drought over Indonesia, New Guinea, and Northern Australia; to the east, drought commonly occurs over Northern Brazil. This year's El Niño event is one of the strongest on record, and has led to severe drought in Indonesia. Landowners commonly ignite(mostly illegal) fires to clear land and manage agricultural areas for production of pulp, paper and palm oil in Indonesia. Carbon-rich peatland forests, which are usually too wet to burn, go up in smoke. These peatland fires, which smolder underground, release about three times more smoke than a standard forest fire.

Figure 3. Smoke from huge fires in Indonesia drift westwards all the way to India in this GMS satellite image from NOAA taken at 04:25 UTC October 21, 1997. Image credit: AFP/AFP/Getty Images.

The fires of 2015: comparable to the fires of 1997
Severe drought during the strong 1997 - 1998 El Niño hit Indonesia and neighboring countries, resulting in a series of massive peatland and forest fires that were triggered by slash-and-burn agriculture. The fires produced a noxious yellow haze that covered an area about 2000 by 3000 miles in area for months. Estimates of the economic damage to Indonesia alone were estimated at $9.3 billion by EM-DAT, the international disaster database, making it their most expensive natural disaster in history. The 1997 - 1998 fires were also the most expensive weather-related disaster in the history of Singapore (damages estimated at $9 billion by the Singaporean government, due to increased healthcare costs and disruptions to air travel and business.) According to the 6 November 2002 issue of Nature magazine, the fires in Indonesia released huge amount of carbon dioxide—equivalent to 13 - 40% of the total amount released annually from human burning of fossil fuels. Indonesia's yearly greenhouse gas emissions are somewhat uncertain, due to the large unknowns associated with deforestation and burning of their forests, but the nation may be the world's fifth largest emitter of greenhouse gases. According to an October 9 article at Climate Progress by Samantha Page, land use, including peat and forest fires, accounts for 63 percent of Indonesia’s greenhouse gas emissions. In September 2015, Indonesia promised that it would not increase these emissions over the next 15 years if it receives international support.

Video 1. Greenpeace Indonesia drone video footage showing slash and burn tactics in Indonesia and peat fires in September, 2015. Instead of deep red flames tearing down trees, the smoke is actually emerging from underground from peat that is burning up to 10 metres (33 feet) deep; 40% of this year’s Indonesia fires have been on peatland. Peatland fires were also a major problem in Russia during the record heat wave of 2010.

Wunderblogger Steve Gregory has an update on El Niño and the latest 2-week outlook in his Monday afternoon post.

Jeff Masters
Categories:Fire El Niño

Wildfires Rage across California; Tropics Quiet for Now

By Dr. Jeff Masters
Published: September 14, 2015
The explosive fire behavior that many Californians have been fearing all summer came to fruition over the weekend about 70 miles north of San Francisco, as the Valley Fire metastasized from an estimated 400 acres on Saturday to 50,000 acres on Sunday (see timeline at bottom of this page). The fire roared across the community of Middletown on Saturday night, prompting hasty evacuations and apparently destroying large parts of the town. One death has been confirmed by the California Department of Forestry and Fire Protection, and four firefighters from a helicopter crew were hospitalized with second-degree burns. Officials have had trouble confirming the amount of damage as the fire continued to rage nearby, but the National Interagency Fire Center reported in its daily update on Monday that at least 412 structures had been lost. The fire was zero percent contained, and close to 20,000 people have had to evacuate.

Two other large wildland fires are afflicting central California. The Butte Fire, which has scorched 65,300 acres and destroyed at least 214 structures since Wednesday, is now 25 percent contained, with more than 4500 firefighters on the scene and many structures still threatened. The long-burning River Complex Fire, which has roamed across 76,614 acres of far northern California since July 30, is 50 percent contained.

Figure 1. Firefighters create a firebreak near a home in Middletown, California, early on Sunday, Sept. 13, 2015, just ahead of the fast-growing Valley Fire. Image credit: AP Photo/Elaine Thompson.

Figure 2. A kitchen stove sits among the remains of a home on Sunday, Sept. 13, 2015, destroyed by the Butte Fire near Mokelumne Hill, California. Image credit: AP Photo/Rich Pedroncelli.

Figure 3. The infrared signal from the Valley Fire was brighter and larger than Reno, NV, on this image collected early Sunday morning, September 13, 2015, by NASA’s Visible Infrared Imaging Radiometer Suite (VIIRS). Image credit: NWS/Sacramento.

As discussed in this blog a couple of weeks ago, September and October are often the worst months for wildfire in California. The region’s Mediterranean climate leaves it high and dry during summer, so the impact of any drought during the previous winter’s wet season becomes exacerbated by the heat of summer and by the strong winds brought by autumn frontal systems and offshore Santa Ana winds. California is in the midst of a four-year drought on par with anything in the century-plus precipitation record, and state temperatures this year are the warmest on record by far. A new analysis by Tom Di Liberto illustrates how tough it will be for California to dig itself out of its multiyear precipitation deficit: every region in California would need record-smashing rainfall this winter in order to bring the five-year totals (2011-12 through 2015-16) merely up to average.

Strong El Niños often bring wet conditions to Southern California, and the intensity of the emerging El Niño event may be enough to extend those above-average rainfalls into the central part of the state, as noted by the NOAA Drought Task Force in a report last month. However, even unusually heavy precipitation may not yield an above-average snowpack in the Sierra Nevada that could help boost water supplies next summer. Snowpack will depend hugely on how cold it is when the biggest storms hit the Sierra, and temperatures are at record warmth both globally and regionally.

Did pyrocumulus play a role?
I asked Daniel Swain, a Stanford University doctoral student and author of the excellent California Weather Blog, to weigh in on the situation. He responded late Sunday night with some clues as to what might have made the Valley Fire behave so explosively.

“It has been really disconcerting to watch this event to watch unfold over a little more than 24 hours. It became pretty clear last night that a true firestorm was underway--50,000+ acres in less than 24 hours and 40,000+ acres in less than 12 hours! What's amazing is that weather conditions were not particularly severe from a fire danger perspective. While there were some gusty winds and warm temperatures, that's not at all unusual for that part of the world. One strange thing did happen, though: a mid-evening ‘heat burst’/gusty wind event seems to have occurred across the North Bay and Lake County area yesterday, possible due to downdrafts from very weak mid-level convective clouds in the area. I've been sent a couple of photographs that suggest that the pyrocumulus cloud from the fire itself may have played a role in this strange event (which I followed with some of the wunderground PWSs, actually!), which would not be that surprising given the magnitude of the fire event. Still, the fact that the fire spread as fast and as far as it did given ambient weather conditions is nothing short of extraordinary.”

Pyrocumulus are the bubbling, cumuliform clouds that often form above large, intense wildland fires. The most spectacular pyrocumulus are sometimes called pyrocumulonimbus for their close similarity to cumulinumbus clouds, sometimes including lightning and anvil-shaped cirrus clouds. Pyrocumulonimbus can even inject aerosols into the stratosphere, according to NASA expert Michael Fromm and colleagues in this open-access article published in 2010 by the Bulletin of the American Meteorological Society. A NASA Earth Observatory article documents spectacular pyrocumulus captured in July 2014 by NASA’s Terra and Aqua satellites during California wildfires.

Figure 4. This view of a developing pyrocumulus cloud above the Oregon Gulch fire, a part of the Beaver Complex fire, was taken from an Oregon Air National Guard F-15C on July 31, 2014, at 8:20 pm PDT. Image credit: James Haseltine, via NASA Earth Observatory.

The role of drought and heat
In his email, Swain also stressed the preconditioning role of this year’s unprecedented combination of drought and heat:

“in some ways, this fire is a realization of widespread fears that California's worst drought on record had created the potential for truly extreme fire behavior this summer and fall. CALFIRE, the state agency tasked with fighting wildfires in California, has been emphatically and explicitly stating that the kinds of extreme fire behavior being observed on the Valley Fire (and other California fires this year) is not something that has been previously observed, and can be attributed directly to the severity of the ongoing, multi-year drought. This kind of on-the-ground assessment is consistent with a number of recent studies suggesting that the observed combination of extremely low precipitation and record-high temperatures is unprecedented in modern California. It's also a very sobering reminder that while many of the impacts of a severe drought are not as conspicuous as those during a more acute meteorological disaster--like a flood or a tornado--sometimes they can be truly and immediately devastating.

As for the week ahead, Swain’s outlook isn’t exactly optimistic:

“The Valley Fire still has zero containment, and is still spreading quickly. Clouds clear tomorrow and winds will start to pick up Tuesday in advance of that weak trough. I'm a bit worried about these pre-frontal winds (could hit 30-40 mph in the fire area), even though the trough itself may drop some light showers in the region. Does look warmer and drier once again after that, so it would be a temporary reprieve at best. Meantime, it seems that Linda's remnants will bring some rain to Southern California early this week (though the models seem to be all over the map with location/amount). If the higher end totals pan out, it'll put a temporary damper on fire season south of Santa Barbara (for perhaps a week or so), but historically that amount of rainfall does very little to mitigate the coming Santa Ana season, which is when most of SoCal's major fires occur.”

A rare September weekend: No tropical cyclones on Earth
We’re just past the climatological peak of the Atlantic hurricane season, and close to the peaks of North Atlantic hurricane and typhoon production as well. Yet for most of this weekend, we had no officially classified tropical cyclones anywhere on the planet. The disturbance shown just east of Vietnam in Figure 5 evolved into short-lived, minimal-strength Tropical Storm Vamco, which was bringing heavy rains early Tuesday local time as it approached the central Vietnam coast (see Figure 6). Varco’s formation ended a 54-hour streak with no tropical cyclones on Earth, the longest such streak to occur in any September since 2009, according to WU blogger Phil Klotzbach (Colorado State University).

Figure 5. At 1400 GMT (10:00 am EDT) on Sunday, September 13, 2015, there were no tropical cyclones anywhere on the planet. The disturbance shown east of Vietnam later became Tropical Storm Vamco. Image credit: Brian McNoldy, University of Miami/RSMAS.

Figure 5. Tropical Storm Vamco (purple blob at center) was moving onto the coast of Vietnam at 1611 GMT (12:11 pm EDT) on Monday, September 14.

Figure 7. This METEOSAT-9 satellite image, collected over the eastern tropical Pacific at 1500 GMT on Monday, September 14, shows tiny Invest 93L (left) and much larger Invest 95L (right). Image credit: NOAA/NHC.

Once Vamco is officially declassified, we may get a second global break from tropical cyclone activity before the next Atlantic system spins up. The most likely candidate is Invest 93L, located several hundred miles west-southwest of the Cape Verde islands at midday Monday. The National Hurricane Center gives 80% odds that this system will become a tropical cyclone by Wednesday. Models are in fairly close agreement that this system will develop into Tropical Storm Ida by midweek, but they also agree it should be recurving sharply by that point, posing no threat to North America or the Caribbean. A much larger tropical wave closer to the African coast, newly designated Invest 95L, is worth watching for potential development later this week. NHC gives this wave 40% odds of becoming a tropical cyclone by Saturday as it enters the central tropical Atlantic. Invest 94L, centered just east of Tampico, Mexico, is associated with a large area of showers and thunderstorms extending into the central Gulf of Mexico at the tail end of a decaying cool front. This system has a chance of developing into a short-lived tropical cyclone over the next several days (NHC gives it 30% odds over the next five days). It would most likely end up tracking westward into Mexico, although its slow development and weak steering currents add some uncertainty to the long-term outlook.

Bob Henson

Video 1. This heart-stopping video was taken by residents evacuating the Anderson Springs area, about five miles northwest of Middletown, California, at 8:30 pm Saturday, September 12, as the Valley Fire roared into the area. Image credit: mulletFive.
Categories:Fire Hurricane

U.S. Wildfires 2015: Are The Worst Yet To Come?

By Dr. Jeff Masters
Published: September 2, 2015
Thus far, 2015 has been one of the worst U.S. wildland fire seasons since modern records began. More than 8.2 million acres have burned across the nation as of September 1, an area larger than Massachusetts and Rhode Island combined. Across the last ten years, that’s the largest amount of fire-scorched U.S. acreage for the January-August period, and it’s close to 50% above the decadal year-to-date average. We are well ahead of the pace set in 2007, when 9,328,045 acres burned, the highest annual total in records going back to 1960.

Figure 1. Flames from a backfire operation burn behind an emergency vehicle near the Rocky Fire on August 3, 2015, near Clearlake, California, north of San Francisco. Some 3,000 firefighters battled the Rocky Fire, which burned more than 80,000 acres and destroyed almost 100 residences and outbuildings. Image credit: Justin Sullivan/Getty images.

There’s a more complex story hiding behind these factoids. Certainly there have been some intense and large fires across the Pacific Northwest, pumping out smoke that’s reddened skies and clotted lungs across large swaths of the nation. But up until August, the main factor behind this year’s large wildfire acreage (as explained by Tom Yulsman at Discover’s ImaGeo blog) was the extent of fire in Alaska. More than 5.1 million acres had burned across the state as of September 1, most of it by midsummer. With Alaska’s fire activity now slowing down, the state’s total affected acreage will likely rank second behind 2004, when a total of 6,590,140 Alaskan acres went up in flames.

It was clear by early summer that the Pacific Northwest was in line for a potentially rough fire season, with long streches of record spring and summer heat following a winter with record-low snowpack. Simply having a parched landscape doesn’t automatically translate into big fire, though. If strong, dry winds are absent; if fires aren’t triggered by lightning and/or human activity; and/or if firefighters manage to tamp down fires quickly, then the potential for disaster may go unrealized. Wildfires didn’t begin taking full advantage of the Pacific Northwest’s primed-for-fire condition until mid-August, when the Okanogan Complex roared to life across north-central Washington. Now the state’s largest assemblage of wildfires on record, the Okanogan Complex (40 percent contained as of Tuedsay) has destroyed more than 170 homes.

Figure 2.The Significant Wildland Fire Potential Outlook for September 2015 shows above-normal risk across parts of four western states, as well as a small part of central Texas. Image credit: National Interagency Coordination Center.

On August 13, officials upgraded the National Preparedness Level for wildland fire to category 5, the highest, meaning that multiple major fires have the potential to exhaust all of the nation’s firefighting resources. This is the first category-5 ranking since a week-long stretch in August 2013, and the fifth such period in the last ten years. Cooler temperatures should continue to tamp down the fire risk in Alaska this month, but it’s far too soon for other western states to rest easy. The latest monthly outlooks for wildland fire potential, issued on Monday by the National Interagency Coordination Center, show an above-normal risk of significant wildfire in September across eastern Washington, northeast Oregon, and far northwest Montana, as well as the Sierra Nevada and coastal mountains south of the Bay Area in California. By October, the risk is expected to return to near normal over the Pacific Northwest and central California, but the highly populated belt of Southern California is still targeted for above-normal risk.

Why fall is the most-feared time for wildfire in California
California’s Mediterranean climate means that rainfall is focused in the period from late fall into spring, with the landscape then getting progressively drier until the next wet season kicks in. This sets up prime conditions for wildland fire during the typically warm, dry weather of September and October, sometimes goosed by strong offshore winds (dubbed the Santa Ana wind in the L.A. area). Late October 1991 brought the horrific Oakland hills firestorm, which destroyed more than 2,800 homes and killed 25 people, and Southern California’s record-setting wildfire seasons of 2003 and 2007 both peaked in October.

Figure 3. Meg Tallberg (left), whose home was not damaged by fire, offers her support to neighbor and friend Jenny Fratis (right), whose house (background) was destroyed in the Witch Fire, as residents returned to Rancho Bernardo in California's San Diego County on 25 October, 2007. Image credit: Robyn Beck/AFP/Getty Images.

This year, California is entering fire season after four years of drought, culminating in what’s been the warmest year for California in more than a century of recordkeeping. Although some unusual summer rains have provided dabs of relief across the far southeastern desert, much of the landscape across central and southern California remains tinder-dry. Some 46% of the state is now in exceptional drought, the highest ranking assigned by the National Drought Mitigation Center in its weekly U.S. Drought Monitor. That’s down a bit from 58% at this time a year ago, but the impacts of long-term drought in the hardest-hit areas remain severe. In August, a study from the University of California, Davis, estimated that the ongoing drought will cost California about $2.7 billion in 2015. Several intense, destructive fires have already struck the state, including the small but frightening, interstate-jumping North Fire east of Los Angeles in mid-July and the huge Rocky and Jerusalem Fires north of San Francisco in late July/early August.

The main questions awaiting the West’s fire-prone areas this autumn--questions that forecasters can’t answer with confidence--is how often and where windy frontal systems and/or strong offshore flow will materialize. NOAA’s seasonal outlook for September through November maintains above-average temperatures throughout the West Coast states, with precipitation below average in the Pacific Northwest and above average over southern California. The strengthening El Niño gives SoCal a good chance at above-average rains this winter, but the heaviest Niño-related rains often don't arrive till December/January.

Figure 4. While in Alaska, WU art director Lauren Moyer captured the not-so-common sight of a virtually cloud-free Mount Denali on August 3, 2015. In the foreground is a WU personal weather station, MEVCA2. Image credit: wunderphotographer moyerdestroyer.

Climate change and wildfire risk
One of the key points made by President Barack Obama in his visit to Alaska this week (including Wednesday’s scheduled stop north of the Arctic Circle, the first ever by a president in office) is the role of human-induced climate change in exacerbating wildfire risk across the state. In a speech delivered Monday in Anchorage, Obama noted: “Alaska’s fire season is now more than a month longer than it was in 1950. At one point this summer, more than 300 wildfires were burning at once.” The lengthening fire season in Alaska reflects a global trend: a new open-access analysis published in Nature Comunications in July found that 25% of Earth’s vegetated surface saw fire seasons grow longer from 1979 to 2013 by an average of close to 20%.

Figure 5. Areas that have experienced changes in the frequency of long fire weather seasons (at least one standard deviation above the historical average) during the period 1996-2013 compared with 1979–1996. Reds indicate areas where fire weather seasons have lengthened or long fire weather seasons have become more frequent. Blues indicate areas where fire weather seasons have shortened or long fire weather seasons have become less frequent. Image credit: Figure 3(b), “Climate-induced variations in global wildfire danger from 1979 to 2013,” W. Matt Jolly et al., Nature Communications 2013.

Alaska has warmed more quickly than the rest of the nation over the last 60 years, with annual average temperatures in Alaska climbing by about 3.0°F over the period from 1949 to 2014. The warming has come in phases, according to the Alaska Climate Research Center, with temperatures spiking in the 1970s and then plateauing at a “new normal” for several decades before a new level of warmth was hit in 2014, continuing into this year. The period Jan-July 2015 was Alaska’s second warmest in 91 years of recordkeeping, according to NOAA’s National Centers for Environmental Information. The U.S. National Climate Assessment, published in 2014, had this to say about Alaska’s evolving climate and fire risk: “Both wetland drying and the increased frequency of warm dry summers and associated thunderstorms have led to more large fires in the last ten years than in any decade since record-keeping began in the 1940s….More extensive and severe wildfires could shift the forests of Interior Alaska during this century from dominance by spruce to broadleaf trees for the first time in the past 4,000 to 6,000 years.”

Figure 6. Annual average temperature across Alaska, 1949 – 2014. Image credit: Alaska Climate Research Center.

Wildfires are the complex product of many variables, including forest management, fire suppression, temperatures and moisture, ignition sources, and firefighting practices. Prior to European settlement, gigantic fires were part of the natural ecosystems across much of North America. In a blog post from 2013, Andrew Revkin discusses the historical context of U.S. fire suppression and its role in helping lay the groundwork for today’s megafires. Whatever factors have led to the forests we have today, their ability to burn intensely is being stoked by rising temperatures that intensify the impacts of naturally occurring drought, a point illustrated vividly this year from California to Washington and emphasized in several recent studies (including this one, published just this week in Geophysical Research Letters). There will be some inevitable randomness in the final, fateful steps (weather events, arsonists, etc.) that lead from a particular parched landscape to a devastating fire. We’re very unlikely to see the entire West in flames anytime soon (thankfully!), but it’s reasonable to expect that heat unprecedented in modern times and dried-out vegetation will sometimes lead to fires more intense and/or widespread than ever before seen by residents of a given area. With ever-larger numbers of Americans choosing to live amid western forests, and cities such as Oakland and Los Angeles adjoining fire-prone areas, the risks to life and property will only rise with time.

Figure 7. It’s a hurricane! It’s a typhoon! It’s both! Dan Lindsey (CIRA) posted this tongue-in-cheek analysis of Kilo, using a visible image from Japan’s Himiwari-8 satellite, as the storm straddled the International Date Line on September 1, 2015. Hurricanes are reclassified as typhoons when they move west across the Date Line. The Sydney Morning News asked whether Kilo should be called a “hurriphoon” or a “typhane.” Kilo was officially reclassified from Hurricane Kilo to Typhoon Kilo at 0600 GMT on September 1. Image credit: RAMMB/CIRA/JMA.

Tropics calming down
After weeks of hyperactivity, the Northern Hemisphere tropics are beginning to calm down for the time being. The 00Z Thursday morning run of the GFS model was not predicting any new tropical cyclones to develop anywhere in the world during the next seven days, though the European model was showing possible development next week of a tropical wave expected to come off the coast of Africa this Friday. This wave is expected to move westwards at about 15 mph towards the Lesser Antilles Islands; NHC did not mention this wave in their 8 am EDT Wednesday Tropical Weather Outlook. Tropical Storm Fred continues to weaken in the far eastern North Atlantic; likewise, Hurricane Jimena in the Northeast Pacific and Hurricane Ignacio in the Central Pacific are gradually spinning down. Only Typhoon Kilo is expected to resurge over the next several days. Currently almost stationary just west of the International Date Line, Kilo should gradually accelerate westward across warm waters south of a subtropical ridge, gaining strength along the way and perhaps reaching Category 4 status once again by the end of the week. Today (September 2) is Kilo’s 13th day as a tropical cyclone, and this morning's run of the GFS model predicted that Kilo would remain a tropical cyclone for at least nine more days. According to the National Hurricane Center, the longest-lived tropical cyclone in the satellite era is Hurricane/Typhoon John, which was tracked for 31 days during August and September 1994.

WU contributor Phil Klotzbach has a new post on the recent frenzy of North Central Pacific activity; see also his two-part entry on record-setting action across the Northern Hemisphere as a whole, posted on August 25 and August 28.

We’ll be back with another post on Thursday.

Bob Henson and Jeff Masters

Big Contrasts this Weekend: Roasting Out West, Soaking Back East

By Dr. Jeff Masters
Published: June 25, 2015
The atmosphere over North America will slide back into a familiar pattern this weekend, as a powerful upper ridge and record heat take hold of the Pacific Northwest and western Canada while an unusually strong upper low for late June brings wet, cool conditions from the Ohio Valley through the mid-Atlantic into New England. It’s yet another variation on the warm-west/cool-east pattern that predominated through much of 2014 and early 2015.

Sizzling temps on tap for Pacific Northwest
While it’s been an unusually hot, muggy June across much of the Southeast, the burners will soon be going full blast out West. Models are consistent in building strong high pressure across the western states late this week into next week. The results will be scorching temperatures, especially in parts of eastern Washington and Oregon where warm, dry weather in recent weeks has left the ground already parched. Highs are projected to range from 100°F to 110°F over most of the next 4 to 6 days across a large area. Excessive heat watches are in effect for both Portland and Seattle. Here are some of WU’s forecast highs compared to monthly and all-time records. (For more, see the roundup by Jon Erdman at

—Spokane, WA: Forecast high 102°F (Sunday); All-time record is 108 degrees on July 26, 1928 and Aug. 4, 1961
—Boise, ID: Forecast high 106°F (Sunday); All-time record is 111 degrees on July 19, 1960 and July 12, 1898
—Salt Lake City, UT: Forecast high 103°F (Monday); June record is 105 degrees on June 28-29, 2013
—Portland, OR: Forecast high 99°F (Saturday); June record high is 102 degrees on June 26, 2006
—Reno, NV: Forecast high 102°F (Friday and Saturday); June record is 104 degrees on June 16, 1940
—Missoula, MT: Forecast high 102°F (Sunday and Monday); June record high is 100 degrees on Jun. 29, 1937 and Jun. 13, 1918.

The heat may abate slightly by the middle of next week over the Pacific Northwest, but longer-range models suggest unusual warmth continuing across much of Canada. There are also hints that a significant heat wave could develop over parts of Europe toward the latter part of next week and beyond, as a highly amplified jet-stream pattern sets up there. The WU extended forecast brings Paris into the mid-90s Fahrenheit for several days, starting next Wednesday.

Figure 1. Temperatures will be 10°F to 30°F above average across large parts of the western United States and Canada, while much of the eastern U.S. will be unusually cool, according to the forecast for 0000 GMT Tuesday, June 30, produced by the 1800 GMT Wednesday run of the GFS model. Image credit: Climate Reanalyzer/University of Maine.

Fire risk increasing over western U.S., Alaska
By recent standards, it’s been a relatively quiet year thus far for wildland fire across the United States. The total amount of land affected by fire through Tuesday, June 23, stands at 885,842 acres, according to the National Interagency Fire Center. That’s slightly above last year’s total through June 23, but well below each of the years from 2005 to 2013. The threat of wildfires should begin ramping up this weekend, though, with record heat and dry lightning storms over parts of California, Oregon, and Washington, as well as western Canada and Alaska. On Wednesday afternoon, more than 1,000 people had to flee a fast-growing 350-acre wildfire near Interstate 5 in Santa Clarita, CA, just north of the San Fernando Valley.

Figure 2. Smoke from the Washington Fire rises over the Sierra Nevada range south of Lake Tahoe as viewed from between Minden and Carson City, NV, on Monday, June 22. The wildfire had grown to over 20 square miles in hazardous and inaccessible terrain and was moving closer to structures, officials said. The Lake Tahoe area saw record-low amounts of snowpack this past winter. Image credit: Jim Grant/ Nevada Appeal via AP.

The greatest fire risk this weekend will be around the edge of the strong high pressure cell taking shape over the interior West. In and near the Cascades, enough moisture should be present for scattered thunderstorms with little rain but gusty winds and lightning. Combined with very hot weather and dry vegetation, this is among the most dangerous scenarios for wildfire risk. Lightning is the main cause of wildfires in the Pacific Northwest, according to Cliff Mass (University of Washington), who outlines the upcoming risk in detail in a blog post. “The bottom line is that with very dry conditions in place, multiple lightning-caused fires are quite possible. Fire folks need to get ready,” said Mass. The fire danger is also high to extreme over much of western British Columbia. The NOAA Storm Prediction Center has not yet outlined any high-probability areas in its 3-8 day fire weather outlook, but the discussion issued Wednesday afternoon notes the possibility of an upgrade as the time period draws closer and confidence in model solutions increases.

Figure 3. Smoke cloaks the skies above Fort Wainwright, Alaska, near Fairbanks, on Wednesday. The smoke is a byproduct of several large wildland fires burning in central Alaska. Image credit: Stephanie Frank.

Most of the major U.S. fires this year to date have been in Alaska, where sporadic bursts of record heat during the spring and early summer have dried out vast stands of forest and brushland. Eleven fires affecting more than 1000 acres each were in progress as of Wednesday, with six of those exceeding 10,000 acres. Several factors are pushing Alaska toward longer and more intense fire seasons, as outlined by Climate Central in a report published Wednesday. The state is warming twice as quickly as the U.S. average--almost 3°F since the 1950s—and the average fire season has lengthened by roughly 40 percent in the last 60 years. Hot temperatures from May to July are strongly related to the frequency and severity of fire seasons in Alaska.

Large fires (more than 1000 acres) have grown far more common in the tundra-dominated Arctic portion of Alaska: such fires occurred in only three years from 1950 through 1969, but 33 such fires have struck the Alaskan Arctic since 2000. “We’re starting to see a tundra-fire regime emerging within the past few decades,” said Todd Sanford (CIRES), the lead author of the report. Earth’s largest tundra fire on record occurred in 2007, when about 250,000 acres (380 square miles) were scorched in the vicinity of the North Slope’s Anaktuvuk River. Such a lightning-triggered fire was once virtually impossible on the damp, chilly tundra. Lake sediments from the region around the Anaktuvuk fire showed no evidence of any other major fires in the last 5,000 years. Further south, wildfire is paving the way for an infusion of deciduous trees into the evergreen forests of the Alaskan interior. According to the 2014 U.S. National Climate Assessment, “More extensive and severe wildfires could shift the forests of Interior Alaska during this century from dominance by spruce to broadleaf trees for the first time in the past 4,000 to 6,000 years.”

A stormy week for Midwest, mid-Atlantic
A strong polar jet stream from the Corn Belt to the East Coast has been ferrying intense thunderstorms from west to east all week. Tuesday brought one of the biggest severe weather outbreaks of 2015, with severe storms sweeping through the mid-Atlantic corridor into New England. At the peak of the storms, some 770,000 people were without power, and widespread tree damage was reported.

Figure 4. A huge mesoscale convective complex (MCS) sprawls across the upper Midwest in this infrared satellite image taken at 8:15 a.m. CDT on Monday, June 22. The pink shadings over northern Iowa and southeast Minnesota correspond to the highest cloud tops associated with the most vigorous thunderstorms. Image credit:

Figure 5. Tornado paths and strengths across northeast Illinois on Monday evening, June 22. Image credit: NWS Chicago.

One of the most powerful storms pushed through southeast Pennsylvania into southwest New Jersey, where power outages exceeded those from Superstorm Sandy and the 2012 derecho. Winds gusted to 85 mph in Gloucester County, NJ, and to 72 mph at Philadelphia International Airport, just a few weeks after outflow from a weak shower on April 22 brought 71-mph winds. The city has recorded gusts that strong only four other times in its weather history.

The day before the mid-Atlantic got slammed, Monday brought a preliminary total of 19 tornadoes, with 9 of them from a long-lived supercell that carved a path just southwest of Chicago (see Figure 5). A long-track, high-end EF3 twister that struck near Coal City was the strongest observed in the Chicago metro area since the deadly F5 Plainfield tornado of August 28, 1990. Another EF3 was reported near Marysville, Iowa. At, Jon Erdman produced this assortment of eye-popping imagery from Monday’s and Tuesday’s storms.

Figure 6. Gary Rink walks behind his home on Tuesday, June 23, in Coal City, Ill., after a tornado passed through the area Monday evening. The community of about 5,000 residents is located about 60 miles southwest of Chicago. Image credit: AP Photo/Charles Rex Arbogast.

Wet weekend on tap for Northeast
Though at least it’s arriving a week before the Fourth of July holiday, a rainy, cool storm system will likely put a big damper on outdoor activities this weekend from the Ohio Valley into the mid-Atlantic and New England. The west-to-east jet stream that’s powered storms all week will buckle into a pronounced upper-level low that will move slowly across the region. A double-barreled surface low may develop, similar to the configuration seen in many nor’easters. Cool temperatures should tilt the odds away from thunderstorms toward steady rain over the coastal cities, where 1” to 3” of rain possible. Heavier downpours could fall over the upper Ohio Valley and Appalachians. With 9.57” reported this month through Wednesday, Baltimore has already landed the second-wettest June in its 145 years of weather history. The record of 9.95”, set in June 1972, could be eclipsed by an inch or more before the month is out.

Bob Henson

Figure 7. Projected three-day precipitation totals from the NOAA Weather Prediction Center, for the period from 1200 GMT June 25 to June 30. Image credit: NWS/WPC.

Figure 8.. The setting sun illuminates mammatus clouds over Pottsgrove, PA, in the wake of Tuesday’s severe storms. Image credit: wunderphotographer Jerry1481.

California Wild Fire Update

By Chris Burt
Published: September 23, 2014
California Wildfire Update

The King Fire, east of Sacramento in California, has now charred 90,000 acres and burned at least 32 structures including 10 homes. It is now 35% contained thanks to a cool, moist weekend. However, the next two days will be critical in its containment since weather conditions have changed back to windy and warm.

A wildfire burns along the shores of Bass Lake in the central Sierra Mountains on September 14th. This was one of several wildfires that have burned across the central Sierra region so far this month. Photo by Darwin Atkeson/AP.

This Tuesday and Wednesday (September 23-24) will be the make it or break it point so far as containing the 90,000-acre King Fire that is threatening 12,000 homes in El Dorado and Placer Counties (about 50 miles east of Sacramento). As of Tuesday, September 23rd, 2,800 people have been ordered to evacuate their homes.

Map of active wildfires in northern and central California as of Tuesday, September 23rd. The round icons represent new wildfires (that have begun in the past week) and the square icons currently active fires that began more than a week ago. The red shaded area is currently under Red Flag warnings. The King Fire is burning in the area indicated in bright red between Reno and Sacramento. Map from Esri Disaster Response Program.

It is already the 2nd largest wildfire of the season (following the 131,996 Happy Camp Complex fire on the Oregon-California border) and has a chance of making it into the ‘top 20’ list of largest wildfires in California history.

The top 20 largest wildfires in California history as of the end of the fire season last October, 2013. The Happy Camp Complex fire has now burned 131,996 acres in far northern California and thus earned its spot as #16 on the list above. It is now 75% under control. Note how 11 of the top 20 largest fires (including the Happy Camp Complex fire) have occurred since the year 2000. Table from Cal Fire,

If the 7,000+ firefighters working on the King blaze can keep it contained through Thursday they may get a break since rainfall is forecast to move into the region later this week.

Forecast QPF rainfall amounts for California through Thursday morning September 25th. The rain, hopefully, will reach the area of the King Fire by Friday. In any case, the rain will almost certainly help suppress the remaining wildfires that are currently burning in the far northern portion of the state, such as the Happy Camp Complex event. Map from NWS-Monterrey.

In spite of this years many calamitous wildfires the amount of acreage so far burned in California has been only slightly above average and, for the U.S. as a whole, only about 50% of normal (using the past 10-year running average) to date.

Total number of fires and acreage burned in the continental U.S. for the year-to-date. It has been a catastrophic fire year so far for California and the Pacific Northwest but much better than usual for the Southwest and Rocky Mountain regions. Table from National Interagency Fire Center, Boise, Idaho.

Nevertheless, the month of October has seen many of the worst wildfire events in California history. It is near the end of the dry season and traditionally the strongest Santa Ana and Diablo wind events (offshore flow) occur. This was the case during the state’s largest and deadliest wild fires on record: the Cedar Fire in October 2003, (see table of ‘Top 20’ above) and the Oakland/Berkeley Hills fire of October 1991 which was the costliest and deadliest wild fire in modern U.S. history. Although only 1,200 acres burned, 3,000 homes were destroyed, 25 lives lost, and over $1 billion in damage was caused.

The largest wildfire in California history occurred in southern California in October 2003. Some 273,000 acres burned consuming 2,800 structures and killing 15. The Oakland Hills fire of October 1991 was even worse (though much smaller) when 3000 homes were destroyed and 25 people were killed. NASA image.

Christopher C. Burt
Weather Historian
Categories:Extreme Weather Fire