The ARkStorm: California's coming great deluge

By: Dr. Jeff Masters , 4:04 PM GMT on January 28, 2011

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For thirty days and thirty nights the rain fell in unending torrents. By the end of the biblical deluge, rivers of water ten feet deep flowed through the streets of Sacramento, and an astounding 29.28 inches of rain had fallen on San Francisco. According to wunderground's weather historian, Christopher C. Burt, in the Sierras, the moist flow of air from Hawaii--often called an "atmospheric river" or the "Pineapple Express"--hit the steeply sloping mountainsides and rose upwards. The air expanded and cooled, causing truly prodigious rains, with the mining town of Sonora receiving 8.5 feet of rain over a 2-month period. The resulting floods inundated California's Central Valley with a lake 300 miles long and 20 miles wide.

The above event occurred in January 1862, and similar extreme rain events have deluged in California seven times in the past 2,000 years--about once every 300 years. Great storms like the flood of 1862 will happen again. If the planet continues to warm, as expected, the odds of such an event will at least double by 2100, due to the extra moisture increased evaporation from the oceans will add to the air. A group of scientists, emergency managers, and policy makers gathered in Sacramento, California earlier this month to discuss how the state might respond to a repeat of the 1862 rain event--the ARkStorm Scenario. The "AR" stands for "Atmospheric River", the "k" for 1,000 (like a 1-in-1000 year event), and of course "ARkStorm" is meant to summon visions of biblical-scale deluge, similar to the great flood of 1862. The team's final report envisions the most expensive disaster in world history, with direct damages and loss of economic activity amounting to $725 billion.

"Atmospheric Rivers" was a term coined in the 1990s to describe plumes of moisture that ride up out of the subtropics into the mid-latitudes along the axis of a cold front. Traditional water vapor satellite imagery does not show these plumes very well, and it was only when microwave satellite imagery from polar orbiting satellites became available in the late 1990s that the full importance of these Atmospheric Rivers came to be revealed. Atmospheric Rivers account for a significant portion of California's cold season rainfall and snowfall, and an entire session was devoted to them at the December 2010 American Geophysical Union (AGU) meeting in San Francisco, the world's largest Earth Science meeting.

Figure 1. The total amount of rainfall one could get if all the moisture in the air were condensed and fell out as rain is called the Total Precipitable Water (TPW). Here, TPW values from microwave satellite measurements are plotted, and show a plume of very moist air connecting the subtropics near Hawaii with Southern California. TPW vales in excess of 20 mm (about 0.8 inches, blue and warmer colors) are "Atmospheric Rivers", and are often associated with heavy rainfall events capable of causing flooding. This Atmospheric River occurred on December 21, 2010, and brought very heavy flooding rains to Southern California. Image credit: University of Wisconsin CIMSS.

California's Delta Region levees at high risk of failure
Much of Central California's water supply and agricultural areas are protected by an antiquated and poorly maintained set of levees along the Sacramento and San Joaquin Rivers that are in serious danger of failure during an extreme flood or major earthquake. The 1,600 miles of levees protect 500,000 people, 2 million acres of farmland, and structures worth $47 billion. Of particular concern is the delta at the confluence of California's Sacramento and San Joaquin rivers, about 80 miles inland from San Francisco Bay. The Delta Region receives runoff from more than 40% of California, and is the hub of California's water supply system, supplying water to 25 million people and 3 million acres of farmland. Key transportation and communication lines cross the region. The Delta Region is home to dozens of islands with highly productive farms that have subsided to elevations as much as 25 feet below sea level. Jeffrey Mount, director of the Center for Integrated Watershed Science and Management at the University of California at Davis, said in a recent interview with MSNBC, "The chances of a catastrophic flood occurring in the Sacramento-San Joaquin Delta sometime in the next 50 years are about two out of three." He called Sacramento, which is only protected to a 1-in-80 year flood by its levees, "the most at-risk large metropolitan area in the country, with less than half the protection that New Orleans had. It is at extreme risk due to levee failure and subsidence."" The most serious catastrophe for the levees in the Delta Region would be a major earthquake occurring during the dry season. Such a quake would allow salt water to intrude from San Francisco Bay, shutting off the fresh water supply for millions of Californians for months. Collapse of the levees during the wet season would be less devastating, as water pressure from the relatively high flow rates of the Sacramento and San Joaquin Rivers would keep salt water from intruding into the Delta Region. There are no good solutions to California's Delta Region water vulnerabilities, but a new $10 billion dollar canal that would route fresh water around the region is being proposed as a possible way Califoria could avoid losing its fresh water supply if a catatrophic failure of the Delta Region levees allowed salt water intrusion to occur.

A 2009 study by the California Department of Water Resources concluded:

The Delta Region as it exists today is unsustainable. Seismic risk, high water conditions, sea level rise and land subsidence threaten levee integrity. A seismic event is the single greatest risk to levee integrity in the Delta Region. If a major earthquake occurs, levees would fail and as many as 20 islands could be flooded simultaneously. This would result in economic costs and impacts of $15 billion or more. While earthquakes pose the greatest risk to Delta Region levees, winter storms and related high water conditions are the most common cause of levee failures in the region. Under business-as-usual practices, high water conditions could cause about 140 levee failures in the Delta over the next 100 years. Multiple island failures caused by high water would but could still be extensive and could cause approximately $8 billion or more in economic costs and impacts. Dry-weather levee failures [also called sunny-day events] unrelated to earthquakes, such as from slumping or seepage, will continue to occur in the Delta about once every seven years. Costs to repair a single island flooded as the result of a dry-weather levee failure are expected to exceed $50 million. The risk of flooding in the Delta Region will only increase with time if current management practices are not changed. By the year 2100, Delta levee failure risks due to high water conditions will increase by 800 percent. The risk of levee failure from a major earthquake is projected to increase by 93 percent during the same period.

The ARkStorm scenario and Great Flood of 1862 are discussed in much more detail by weather historian Christopher C. Burt in his latest post.

Figure 2. Levee failure on the Upper Jones Tract in the Delta Region on June 4, 2004. Image credit: California Department of Water Resources. A 1997 flood in the Delta Region did $510 million damage, damaged or destroyed 32,000 homes and businesses, and left 120,000 homeless.

Wilma pounding New Zealand; Australia eyes two potential new tropical cyclones
With February nearly upon us, the traditional peak of the Southern Hemisphere tropical cyclone season is here. Activity has picked up markedly this week, with the formation of the year's first two Category 4 tropical cyclones, Tropical Cyclone Wilma and Tropical Cyclone Bianca. Wilma passed over American Samoa as a strong tropical storm, and hit Tonga as a Category 3 storm, causing substantial damage to the islands, but no deaths or injuries. Wilma is currently pounding New Zealand's North Island with heavy rains and strong winds, and is the strongest tropical cyclone to affect that country in fourteen years, according to Tropical Cyclone Bianca is expected to skirt the west coast of Australia over the next few days and rapidly weaken, but could bring heavy rains to the coast near Perth when it makes landfall on Sunday as a tropical storm. Of much greater concern for Australia are two potential tropical cyclones that could hit the flood-ravaged state of Queensland next week. Both the European Center and GFS models predict that the remains of Tropical Cyclone Anthony will regenerate into a tropical storm and hit Queensland early next week. A second and potentially more powerful storm is forecast by the European model to form next week in the islands to the east of Australia, and threaten Queensland at the end of the week. The GFS model has backed off on its prediction of such a storm forming. If the cyclone were to form, it would be a serious blow for Queensland, which is struggling to recover from record floods. As reported in the latest Bureau of Meteorology climate statement and flood summary, the past four months (September - December) have been the rainiest such period in Queensland's history, and the resulting flooding disaster has been Australia's most expensive natural disaster in history.

Figure 3. Tropical Cyclone Bianca, the globe's second major tropical cyclone of 2011, as seen at 06:30 GMT on January 28, 2011 by NASA's Aqua satellite. Biana is expected to rapidly weaken and hit the Australian coast near Perth as a tropical storm on Sunday. Image credit: NASA.

Have a great weekend, and I'll be back Monday with a new post.

Jeff Masters

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Quoting sirmaelstrom:
Concerning the artic sea ice extent:

Not the worst it's been, especially considering recent conditions. Why does the NSDIC graph highlight the Oct'06-Feb'07 period? That particular period doesn't really stand out in any way.

its not of any great importance of extent anyway
that will all ways rebound during winter
and in the north that will happen till beginning of may
anyway what matters is the age and most of it is what i call 1st year ice
now first year ice is of a more slush type
faster to melt and clear out not like old ice
which is thicker and harder thats what we need to know
all the ice that has formed since nov
will all ready be melting by july
and continues till near end of sept till refreeze returns
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Quoting DEKRE:

Any anthropologists on this blog?

I would highly suggest Diamond Jared's Collapse


While I am not an anthropologist my kids study the collapse of the Anasazi in school including trips to Crow Canyon.

I don't agree with all the entire thesis of the book but it is excellent reading on how Native Americans were not always good to the land.

There is also an excellent chapter on the Mayan collapse... and the end of the Medieval Warm period in Greenland.
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200. HadesGodWyvern (Mod)
Fiji Meteorological Services
Tropical Disturbance Summary
9:00 AM FST January 29 2011

At 21:00 PM UTC, Tropical Depression 09F (1003 hPa) located at 14.0S 178.3E is reported as slowly moving. Position POOR based on visible/infrared imagery with animation and peripheral surface observations. Sea surface temperature is 29C.

Organization is poor. Convection has been persistent in sectors from north through east to southeast of the system in the past 24 hours and now has increased in the southwest sector. Low level circulation center difficult to locate. System lies along a surface trough and under 250 HPA ridge axis, in a moderately sheared environment. Cyclonic circulation extends to 500 HPA.

Global models have picked up the system and slowly moves is west with slight intensification.

Potential for this system to develop into a tropical cyclone within the next 24-48 hours is LOW TO MODERATE
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199. HadesGodWyvern (Mod)
Tropical Cyclone Warning Center Perth
Tropical Cyclone Advice #41
9:00 AM WST January 29 2011

At 8:00 am WST, Severe Tropical Cyclone Bianca, Category Three (965 hPa) located at 27.5S 107.8E, or 920 km west northwest of Perth and 680 km west northwest of Geraldton has 10 minute sustained winds of 70 knots with gusts of 100 knots. The cyclone is reported as moving south at 13 knots.

Hurricane Force Winds
30 NM from the center

Storm Force Winds
50 NM from the center

Gale Force Winds
150 NM from the center in northeastern quadrant
100 NM from the center in northwestern quadrant
150 NM from the center in southern quadrant

Dvorak Intensity: T4.5/4.5/W0.5/24HRS

Bianca is expected to weaken further during today and begin to move towards the southwest corner of the state. As it approaches the coast it will weaken rapidly but there is some risk that Bianca could still have an impact on the South West on Sunday. DAMAGING WINDS with gusts to 100 kilometres per hour are possible southwest of a line Jurien Bay to Albany.

Tides between Jurien Bay and Cape Naturaliste will be higher than expected and may rise above the highest astronomical tide level with ROUGH SEAS, DANGEROUS SURF and COASTAL EROSION. FLOODING of LOW LYING COASTAL AREAS is possible in Geographe Bay. HEAVY RAINFALL is also possible on the southern side of the system with LOCALISED FLOODING. Extensive flooding is not expected.

VERY HIGH to SEVERE FIRE DANGERS are likely near the west coast on Sunday, possibly reaching EXTREME across inland areas south of a line from Geraldton to Leonora to Israelite Bay on Sunday.

Tropical Cyclone Warnings/Watch
A Cyclone WARNING has been declared for coastal areas from Jurien Bay to Albany, including Perth, Mandurah, Bunbury and Busselton.

Forecast and Intensity
12 HRS: 29.9S 109.3E - 50 knots (CAT 2)
24 HRS: 31.5S 112.4E - 40 knots (CAT 1)
48 HRS: 33.0S 119.0E - 25 knots (TROPICAL LOW)
72 HRS: -- --- --

Additional Information

Position based on IR and microwave. Dvorak intensity: Preceding three hours of IR imagery consistently yields DT of 4.5 based on eye pattern. MET is 4.5 based on slight weakening over the past 24 hours. Hence FT and CI remain at 4.5. Weakening is likely to occur soon due to the cooler ocean temperatures [<26C] now that it is moving south of 27S.

The system has started to move into an area of higher shear, currently estimated to be 15-20 knots. This should continue to increase as the system moves further south over the next 24 to 36 hours. Hence rapid weakening is expected in the next 36 hours.

The most likely scenario is that Bianca will weaken below cyclone intensity before it crosses the coast as the strong southeasterlies from the new high push
in and markedly increase the shear. However, there still remains the risk of an impact along the southwest coast of Western Australia on Sunday, particularly if the system moves faster than foercast and crosses the coast earlier in the day.

The next tropical cyclone advice on Severe Tropical Cyclone Bianca will be at 3:00 AM UTC..
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198. HadesGodWyvern (Mod)
Tropical Cyclone Warning Center Brisbane
Tropical Cyclone Advice #4
11:00 AM EST January 29 2011

At 10:00 AM EST, Tropical Cyclone Anthony, Category One (996 hPa) located 15.5S 154.7E, or 940 km east northeast of Townsville and 850 km northeast of Bowen has 10 minute sustained winds of 35 knots with gusts of 50 knots. The cyclone is reported as moving northwest at 4 knots.

Gale Force Winds
60 NM from the center in southern quadrant
60 NM from the center in northeastern quadrant
40 NM from the center in northwestern quadrant

Dvorak Intensity: T2.0/3.0/W1.0/24HRS

Tropical Cyclone Anthony is currently slow moving. Anthony is expected to turn to the southwest today and is forecast to intensify slightly as it approaches the Queensland coast.

Damaging winds are expected to develop about coastal and island communities between Innisfail and St Lawrence late on Sunday.

Tropical Cyclone Watches/Warnings
A Cyclone WATCH is now current for coastal areas from Innisfail to Saint Lawrence.

Forecast and Intensity
12 HRS: 16.3S 153.3E - 40 knots (CAT 1)
24 HRS: 17.7S 151.3E - 45 knots (CAT 1)
48 HRS: 19.8S 146.4E - 35 knots (CAT 1)
72 HRS: 20.5S 140.6E - 20 knots (TROPICAL LOW)

Additional Information

DT hard to define with a lack of convection. FT based on MET with CI held at 3.0 due constraints.

The systems has struggled to develop convection against the diurnal maximum overnight, most likely due to a dry surrounding atmosphere and lack of upper divergence.

The next tropical cyclone advice on Tropical Cyclone Anthony will be issued at 7:00 AM UTC..
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Quoting pottery:

That's not a point that anyone will dissagree with.
But, I am sure that some will....

LOL, many here have taken certain classes to help with that Pottery! :)
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Concerning the artic sea ice extent:

Not the worst it's been, especially considering recent conditions. Why does the NSDIC graph highlight the Oct'06-Feb'07 period? That particular period doesn't really stand out in any way.
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Quoting Neapolitan:

My contention has been and remains that while Native Americans may have unwittingly caused ecological damage, they did not do so just because they wanted to, or for fun, or because they thought they were some special creation and as such had been granted carte blanche to destroy whatever they wanted to. We, on the other hand, are intentionally and recklessly causing unimpeded damage. To me that's a major difference.

That's not a point that anyone will dissagree with.
But, I am sure that some will....
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Quoting DEKRE:

See entry 138

Member Since: November 8, 2009 Posts: 4 Comments: 14167
193. DEKRE
Quoting Neapolitan:

See entry 138
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Quoting DEKRE:

Any anthropologists on this blog?

The myth of the noble savage was actually created in Germany in the second half of the 19th century.It is a myth.

My contention has been and remains that while Native Americans may have unwittingly caused ecological damage, they did not do so just because they wanted to, or for fun, or because they thought they were some special creation and as such had been granted carte blanche to destroy whatever they wanted to. We, on the other hand, are intentionally and recklessly causing unimpeded damage. To me that's a major difference.
Member Since: November 8, 2009 Posts: 4 Comments: 14167
190. xcool
I guess we'll see
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189. xcool
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187. xcool
2011 Atlantic hurricane season will be busy AND La Niña conditions or neutral jmo ..
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185. DEKRE
Quoting FLWeatherFreak91:
If you had any knowledge ...

Any anthropologists on this blog?

The myth of the noble savage was actually created in Germany in the second half of the 19th century.It is a myth.
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Arctic sea ice is trying to make a late growth-season rally. The stronger polar vortex of late during a wickedly strong AMO is likely helping growth rates.

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Quoting DEKRE:
By the way, the Native American Culture....

They were actually quite destructive (eg mass killings of bisons). However, they had the excuse of not knowing better as compared to not wanting to know better
If you had any knowledge of what the Native Americans believe(d), you would never make a comment like this. They knew far more of the relationships in living things than the best ecologists do now. They devoted their lives to living and experiencing the majestic wonder of nature, opposed to how we live now- in a constant fixation on the need to explain every natural occurrence through mathematics.

Whether global warning is a result of our chemistry or not, humanity has been informed that our actions are having an effect on earth and nature, and yet we still are ignorant to this.

The Native Americans knew how to truly live, as many cultures did thousands of years ago, free of monetary attachment, and obsessed with their relationship with Nature.
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180. Skyepony (Mod)
Situation Update No. 14
On 28.01.2011 at 12:47 GMT+2

More rescuers have recovered 830 bodies from flooding and mudslides sparked by more than a week of heavy rains in what is considered Brazil's worst-ever natural catastrophe. Another 518 are still missing and feared dead, according to Civil Defense figures. In addition, more than 21,000 people lost their homes or had to abandon them amid fears of likely collapse. Brazil's rainy season has been particularly severe this year, with flooding also swamping southern Santa Catarina state and Sao Paulo, the economic hub that record its rainiest January in 60 years.
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Hummm, this will certainly cause trouble for some folks..... January global temp below normal? Go figure, seems to be following that SST plunge eh? We have a few more days left however :)
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Quoting Levi32:

If that was aimed towards me, in my post I was just mentioning that thunderstorms has been missing on the south coast of western africa for the last month.

But now they've returned, which are signs of the return to summer.

If you weren't posting that because of my post, then never mind
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IN AWESOME NEWS relating to this year's atlantic hurricane season:

Image and video hosting by TinyPic

Thunderstorms have returned to the southern coast of West Africa.

Although the picture provided above is a day old, the fact remains that thunderstorms have indeed returned to the southern coast of West Africa after a solid month long break.
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don't forget ManBearPig....
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im coo coo for coca coca puffs
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This just proves that global warming and santa claus are working together to disguise the harsh reality Manhattan will be under water in 23 more years.

it needs's filthy....
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162. JRRP
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Quoting Patrap:
I had a alligator fried Po-boy fer Lunch today.

Extra tabasco.

And a Fresca.

Sounds good, Pat. I like Fresca.
Member Since: July 23, 2010 Posts: 1 Comments: 12414
well i see we are having another one of those pissing contests again

Afternoon, KOTG. Inspiring, yes? lol
Member Since: July 23, 2010 Posts: 1 Comments: 12414
159. DEKRE
Why is it people relate snow with low temperatures. You get most snow at temperatures just below freezing - you need water in the air and it takes energy to evaporate enough water. If you go to the arctic tundra - it is cold there, very cold - you will find there is very little snow, it is actually considered a semi-desert.
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Quoting McKnightRider:

I think that next time it's gonna be the Vogons.

What we really need are the Vulcans, passionate
about Logic and Science, not so interested in
data doctoring to reach an end result.
Why are we not talking about records broken?
Oh, wrong record, low not high.

Jan. 27, 2011
Another Snow Blow Slams Northeast
New York Gets 19 Inches, Philadelphia 17; 300K Around D.C. Already in the Dark, Airline Passengers Stranded

New York City typically gets 21 inches of snow a winter. Mayor Michael Bloomberg said the latest storm makes this January the snowiest since the city started keeping records, breaking the mark of 27.4 inches set in 1925. The New York area has been hit with snow eight times since mid-December.;lst;1
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Neap.... thank you for taking my question seriously... I appreciate your response....
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156. DEKRE
I have experienced what even "ordinary" rainfalls can be like. I very much liked to drive between San Diego and the Anza Borrego State Park, over the mountains. One spring under torrential rains, I was stopped by the police - my beautiful road was gone, without trace - just washed away.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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