The ARkStorm: California's coming great deluge

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

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 weatherwatch.co.nz. 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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Levi told me about two weeks ago it was going to be "chilly" down here in so. Fla. on Super Bowl Sunday. Forecast high..70. Good job Levi!
Member Since: Posts: Comments:
Quoting JFLORIDA:
Ignorance and people wasting my time turns me off.

I ignored every anti science poster here and would appreciate them not being quoted especially if it has no application to climate or weather. Certainly I dont want to hear their weather predictions if they are as unsourced and based in opinion.

The only reason I come in here is in hopes of reading referenced material, certainly not to be directed to kook websites or hear amateurs with ludicrous theories about how they have uncovered a vast conspiracy in atmospheric science.

Especially ones that have been wrong and proven so running on five years now in here.


Lot's of "I's" in that, perhaps some therapy might help with your issues with basic nature and its biological functions? Just sayin you think everything is yours to control/? Should we take guidance from you based upon who you are? Is that what you are saying? Someone who cannot get the basic functional principles of life in order? Ya think, I am gonna lead my life, and my family, based upon your deviation of such?

No, I don't think so..........

out >>>>>>>>
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Not sure exactly what isn't right about it, but the storm total rainfall seems off. Says less than 0.25 inch since last night, yet it has been raining more than half of the day, some moderate.



(I'm just WNW of the radar site, ~18 miles)

And obs from nearby:


And other obs: The yard is squishy. (technical quantitative precipitation jargon, sorry)
;-)
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting Grothar:


Could be a hostage situation.



LOL
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Quoting Levi32:


I don't see too much in the way of upwelling. Anthony was too weak.

Levi when will you put out your first hurricane forecast??
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Levi, all I see now is the little spot of lighter orange under the "A" in Anthony on that map.... doesn't look like much of a deterrent.... getting a glum feeling about this one... like Dennis and Floyd 1999.
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May has kicked off the invest season the last 4 years.

We May have to move the Atlantic Season start date to May 15th like the East Pac.
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I'm confused.Okay I know everybody is going to talk about that no good sneaky little storm currently down near australia who's name I won't mention,but I come back,and everybody is talking about how they put neo on ignore,and songs,and stuff.I tell ya this blog can be even craizer at times during the off season,than hurricane season on here.Eh??.But speaking of hurricane season......February is just on our heels,and before you know it,we'll be sitting at our computers again like we did last year,and staring at the calender saying.......It's June 1st already???
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Quoting BahaHurican:
On the south side of that cone, there was an area of cooler waters [upwelling from Anthony?] that would at least potentially cut the fuel potential somewhat.... but that northern approach would be pretty bad all around. That is one hefty storm...

I just realized Central Queensland is like the Yucatan of Oz... just sitting there waiting to get hit by every passing TC... worse than FL, even....


I don't see too much in the way of upwelling. Anthony was too weak.

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Quoting RecordSeason:
803. JRRP

Based on the steering data and the Dvorak rating on the chart provided by Patrap, this thing may take the northern half of the cone for a while, and that is the hottest water in the region.

This could be one baaad mammy whammer right here in like 24hrs.

Hopefully it weakens before landfall.
On the south side of that cone, there was an area of cooler waters [upwelling from Anthony?] that would at least potentially cut the fuel potential somewhat.... but that northern approach would be pretty bad all around. That is one hefty storm...

I just realized Central Queensland is like the Yucatan of Oz... just sitting there waiting to get hit by every passing TC... worse than FL, even....
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Quoting sunlinepr:
I have developed a deep hatred for Yasi.How dare "It" try to strike an area that's trying to recover.Wind shear needs to come a tear it to shreds,with dry air being the cherry on top.
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Quoting BahaHurican:
Dunno if others answered as yet, but something I read earlier today said they had similar flooding in the same general area of Saudi Arabia within the last 12 months....
thanks!!!! I'm curious about that( historically as well as past 5 years) -- will have to check further tomorrow - which also brings me a 5:00AM wake-up -arrrvvvvy - nite all
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Good old Dr. Smith...Oh dear Will...Oh dear.
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feels mo like 10 years gone to me..
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Quoting GeoffreyWPB:
Nea...I think your Kreskin-like avatar may turn a lot of bloggers off.


I was thinking this was more indicative of the smug part. Perhaps we could get him to alter it accordingly :)

I better get go. Gnight all >>>>>>>>>>



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Quoting presslord:


I have only found one sure fire way to avoid argument: saying "Yes, ma'am!"
Man, I musta missed something going up....... I've never hear that in my 27 years of matehood. I got one smart Captain ...LOL

Okay -- no bites on my Saudi question eh? just wondered if they've ever experienced that kind of flooding.... seemed rather bizarre

Night Amigo's hope I don't find any fur, feather or body parts here in the AM ---
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Quoting twincomanche:


That reminds me of the Irish joke about Gallagar and the poker game.


PUHLEEZE WU mail it to me!!!!
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Quoting surfmom:
Curious -- has Saudi Arabia experience flooding like this before?
Jeddah City Saudi Arabia Floods Rain Cars Damage
Link
Dunno if others answered as yet, but something I read earlier today said they had similar flooding in the same general area of Saudi Arabia within the last 12 months....
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Quoting bappit:

Actually, I have him on ignore. Why don't you?
That's a surprise.I guess I'm to nice then.I still didn't put him on ignore after he said I was trolling,saying that last hurricane season was a bust.Hmmmm.Then calling me a 12 year old on top of that when I'm actually 40.Opps.
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Quoting Patrap:
NFC 55

AFC 28


3:33 left in da 4th


What the heck. A score that high?? Sounds like a game worth watching!
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"">
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Quoting Neapolitan:

That's okay; I'm not trying to turn any of them on. ;-)


Lol...See, that was cool. (While some use the Google on Kreskin)
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Quoting twincomanche:


Tis. It's the best thing that ever happened to me. Been through a lot of good times and bad and we have always held hands.


we once went to this Catholic marriage encounter weekend...the nun running one of the workshops suggested that couples should hold hands when arguing...my wife asked, incredulously "But...then how would I be able to smack the crap outta him?!?!?!"
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NFC 55

AFC 28


3:33 left in da 4th
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Quoting GeoffreyWPB:
Nea...I think your Kreskin avatar may turn a lot of bloggers off.

That's okay; I'm not trying to turn any of them on. ;-)
Member Since: November 8, 2009 Posts: 4 Comments: 15276
Nea...I think your Kreskin-like avatar may turn a lot of bloggers off.
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Quoting GeoffreyWPB:


Wow! Congrats! Must be a true love.


Could be a hostage situation.
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Quoting twincomanche:


Forty seven years of marriage confirms this.
Only 10 years in, myself, but I think I have it down.

Like I tell my 6-year-old, my policy is: If mommy is happy, the rest of us are allowed to be. Not guaranteed to be, but the possibility exists.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting atmoaggie:
For the same brutal honesty, but much quicker to the point...there's no reason to a-hole, Nea.

Another great example.

Oh, puh-leez. You seldom post much on here anymore in the way of science, instead simply choosing to focus your vitriol on those who disagree with your contrarian stance. You lob hand grenades and invective at those people, then feign hurt surprise when they respond in kind.

As I say to so many others: please feel free to either ignore me or "Ignore' me; I promise my feelings won't be hurt.
Member Since: November 8, 2009 Posts: 4 Comments: 15276
Quoting twincomanche:
Is there any chance that if everyone in the world ignores Neo that eventually he would go away?

Actually, I have him on ignore. Why don't you?
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Quoting Neapolitan:

I bet you do; I'm sure WUWT has some more anti-science stuff for you to study. ;-)


Rid yourself of your cheap sunglasses! It ain't workin..........

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Quoting twincomanche:


Forty seven years of marriage confirms this.


Wow! Congrats! Must be a true love.
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Quoting twincomanche:


I feel your pain. Been here forever under another name. Purged in the night of a thousand knives. The lack of respect is what I find distressing. That must be because I'm almost as old as Grothar, although no one is quite as old as he.


Just think I have 7 older siblings. Glad you're back, just behave yourself now.
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Quoting twincomanche:


Forty seven years of marriage confirms this.


I need to behave...Pat has my wife's phone ##...
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atmo said a bad word...
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Quoting Neapolitan:

I bet you do; I'm sure WUWT has some more anti-science stuff for you to study. ;-)
Try not to be such an a$$ and your mission would be easier to complete...

I don't remember anyone calling you names (well, not before the last hour) or questioning how well you can grasp science. Yet all you can do is accuse others of such. Sad, really. Respect your fellow human and you'll obtain some yourself, someday.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting presslord:


I have only found one sure fire way to avoid argument: saying "Yes, ma'am!"


(SMILES)
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Quoting Neapolitan:

Ah, Ossqss. Your inability to read and retain is causing you problems again, I see. If you're still unaware of the obvious and proven correlation between rising CO2 levels and rising temperatures, you'll probably find that this forum moves too fast for you. I'd take the time to give you some remedial help, but I really don't have the time or the inclination. Good luck, and please rejoin us when you feel like you can keep up! ;-)
For the same brutal honesty, but much quicker to the point...there's no reason to be a-hole, Nea.

Another great example.
Member Since: August 16, 2007 Posts: 6 Comments: 12463
Quoting Grothar:


You've obviously never been married??? When they come out with 38 ways to AVOID an argument, then I'll buy it.


I have only found one sure fire way to avoid argument: saying "Yes, ma'am!"
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Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather

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