Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 4:32 PM GMT on January 31, 2014
California's first significant snow storm of 2014 hit the Sierras on Wednesday and Thursday, dumping up to 2 feet of snow, with a melted water equivalent of up to two inches. However, this modest snowstorm was not enough to keep the Sierra snowpack from recording its lowest snow amounts in more than 50 years of record keeping during Thursday's Sierra Snow Survey. The survey found a snow pack that was only 12% of normal for this time of year. Until Thursday, the lowest statewide snowpack measurement at this time of year was 21% of average, in 1991 and 1963, according to the Los Angeles Times. Since snowpack in the Sierras forms a crucial source of water for California, the dismal snow survey results are a huge concern.
Figure 1. Frank Gehrke, chief of the California Cooperative Snow Survey Program for the Department of Water Resources, walks leaves a snow covered meadow after the second snow survey of the year near Echo Summit, Calif., Thursday, Jan. 30, 2014. Despite the overnight snow storm the survey showed the snow depth at 12.4 inches with a water content of only 1.4 inches for this location at this time of the year. Gehrke said that while the recent snow fall will help, it is not enough to impact the water supply.(AP Photo)
The forecast: little drought relief in sight
One of the most persistent and intense ridges of high pressure ever recorded in North America has been anchored over the West Coast since December 2012. While the ridge has occasionally broken down and allowed low pressure systems to leak though, these storms have mostly brought spotty and meager precipitation to California, resulting in California's driest year on record during 2013. January 2014 could well be its driest January on record. The ridge inevitably builds back after each storm, clamping down on any moisture reaching the state. Since rain-bearing low pressure systems tend to travel along the axis of the jet stream, these storms are being carried along the axis of the ridge, well to the north of California and into Southeast Alaska, leaving California exceptionally dry. The latest runs of the GFS and European models show that the ridge is now building back, and it appears likely that California will see no significant precipitation until at least February 7. A weak upper level low will move along the coast on Sunday and spread some light rain along the immediate coast, but this precipitation will generally be less than 0.25"--too little to have any significant impact on the drought. The ridge will not be as intense when it builds back, though, which gives me some hope that a low pressure system will be able to break the ridge by mid-February and bring the most significant rains of the winter rainy season to California.
Figure 2. One of the key water supply reservoirs for Central California, Lake Oroville, as seen on January 20, 2014. Image credit: California Department of Water Resources.
Worst California drought in 500 years?
UC Berkeley paleoclimatologist B. Lynn Ingram, author of "The West Without Water: What Past Floods, Droughts, and Other Climatic Clues Tell Us About Tomorrow", said in an interview, “this could potentially be the driest water year in 500 years.” Her research on tree rings shows that California has not experienced such an extreme drought since 1580. "If you go back thousands of years, you see that droughts can go on for years if not decades, and there were some dry periods that lasted over a century, like during the Medieval period and the middle Holocene. The 20th century was unusually mild here, in the sense that the droughts weren’t as severe as in the past. It was a wetter century, and a lot of our development has been based on that." It's no wonder, then, that the overall agricultural impact of the drought could reach $1 billion this year, according to the Fresno-based Westlands Water District.
California's drought woes are part of an on-going 14-year Western U.S. drought that began in 2000, and peaked between 2000 - 2004. A 2012 study titled, Reduction in carbon uptake during turn of the century drought in western North America, found that the 2000 - 2004 drought was the most severe Western North America event of its kind since the last mega drought over 800 years ago, during the years 1146 - 1151. The paper analyzed the latest generation of climate models used for the 2013 IPCC report, which project that the weather conditions that spawned the 2000 - 2004 drought will be the new normal in the Western U.S. by 2030, and will be considered extremely wet by the year 2100. If these dire predictions of a coming "megadrought" are anywhere close to correct, it will be extremely challenging for the Southwest U.S. to support a growing population in the coming decades.
Megadroughts in the Western U.S. can develop from natural causes, as well, and the current pattern of cooler than average ocean temperatures in the Eastern Pacific and warmer than average ocean temperatures in the Atlantic increase the odds of drought conditions like the ones we have seen during the current megadrought. Edward Cook, director of the Tree Ring Laboratory at Columbia University’s Lamont-Doherty Earth Observatory in Palisades, N.Y., said at a presentation last month at the American Geophysical Union meeting that tree ring data show that the area of the West that was affected by severe drought in the Medieval period was much higher and much longer than the current drought. It is “indeed pretty scary,” Cook said. “One lasted 29 years. One lasted 28 years. They span the entire continental United States." Two megadroughts in the Sierra Nevada of California lasted between 100 and 200 years. Bobby Magill at Climate Center has more on Dr. Cook's presentation in a post, Is the West’s Dry Spell Really a Megadrought?
Figure 3. Normalized precipitation over Western North America (five-year mean) from 22 climate models used to formulate the 2013 IPCC report, as summarized by Schwalm et al., 2012, Reduction in carbon uptake during turn of the century drought in western North America. The horizontal line marks the precipitation level of the 2000 - 2004 drought, the worst of the past 800 years. Droughts of this intensity are predicted to be the new normal by 2030, and will be considered an outlier of extreme wetness by 2100. The paper states: "This impending drydown of western North America is consistent with present trends in snowpack decline as well as expected in-creases in aridity and extreme climate events,including drought, and is driven by anthropogenically forced increases in temperature with coincident increases in evapotranspiration and decreases in soil moisture. Although regional precipitation patterns are difficult to forecast, climate models tend to underestimate the extent and severity of drought relative to available observations. As such, actual reductions in precipitation may be greater than shown. Forecasted precipitation patterns are consistent with a probable twenty-first century megadrought." Image credit: Schwalm et al., 2012, Reduction in carbon uptake during turn of the century drought in western North America, Nature Geoscience 5, 551-555, Published online 29 JULY 2012, DOI: 10.1038/NGEO1529, www.nature.com/naturegeoscience.
Unprecedented Cut in Colorado River Flow Ordered, Due to Drought, my August 2013 post.
Lessons from 2012: Droughts, not Hurricanes, are the Greater Danger, my November 2012 post.
How Two Reservoirs Have Become Billboards For What Climate Change Is Doing To The American West, August 12, 2013 climateprogress.org post by Tom Kenworthy.
Scientists Predicted A Decade Ago Arctic Ice Loss Would Worsen Western Droughts. Is That Happening Already?, June 2013 post by Joe Romm at climateprogress.org.
Twenty Cities At Risk of Water Shortages, August 14, 2013 wunderground news post by Nick Wiltgen
If There's Global Warming...Why Is It So Cold?
It's been top-ten coldest January on record in the Upper Midwest, and much colder than average over much of the Eastern U.S. However, the that isn't the case over other portions of the globe, including the Western U.S. and Alaska. Wunderground's weather historian Christopher C. Burt analyzes the situation in his latest post, How Cold has this January been in the U.S.? He concludes, "this January’s average temperature nationally has probably been close to normal since the western half of the nation has been almost as much above average as the eastern half was below average. The only region that will most likely have experienced a TOP 10 coldest January will be the Upper Midwest." In the U.S., only four stations set all-time low minimum temperature records in January, compared to 34 that set all-time high maximum temperature records. I've been monitoring global temperatures this month, and it appears likely that January will rank between the 5th and 15th warmest January since record keeping began in 1880. Of particular note were the amazingly warm January temperatures in the Balkans. According to weather record researcher Maximiliano Herrera, "over 90% of all stations in the Balkans from Slovenia to Croatia to Bosnia to Serbia To Montenegro to Kosovo etc., have DESTROYED their previous record of warmest January ever (many locations have 100 - 200 years of data.) In many cases the monthly temperatures were 7 - 9°C (13 - 16°F) above average, and the new records were 3 - 4°C above the previous record. This is for THOUSANDS of stations, almost all of them. In Slovenia, for example, Mount Kredarica is the only station in the whole country not to have set its warmest January on record."
Video 1. If There's Global Warming ... Why Is It So Cold? The latest video from climate videographer Peter Sinclair on the Yale Climate Forum website demonstrates that while it was a very cold January in the Midwest, this has been counterbalanced by record warmth over the Western U.S. and Alaska, caused by an unusually extreme kink in the jet stream.
Another Unexpected Disaster That Was Well Forecast. Based in Atlanta, TWC's Bryan Norcross concludes that "WARM GROUND + VERY COLD AIR + SNOW + WORKDAY = CHAOS. If the decision-makers understood the formula above, this information should have been sufficient to trigger a proper response."
Jon Stewart Lays Into Georgia’s Snowpocalypse
Have a great weekend, everyone, and I'll be back Monday with a new post.
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