The ARkStorm: California's coming great deluge
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
Reader Comments
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Nope... much rather you get the pineapple express then us... we get it "all" the time :(
got it.... it's just Calif.... it doesn't affect the rest of the country....
I hear ya... I've always said a major earthquake in Summer would be a huge deal... Can you imagine the California Aquaduct being ruptured everywhere it crosses the San Andreas fault in July... or August?
How would we airlift water to 30 million people in the Metropolitan Los Angeles area?
I didn't know about the vulnerability of the delta region... That's kind of alarming considering how much food comes out of that region. (A LOT)
D
I like San Diego (golf courses).. does that count?
Mind you.. sad to say, since 911 we have never been back to the states.
hahahahahahahahahahaha!!!!! we have the highest taxes in the country, with over 12% unemployment, and you want to raise taxes!!!!!! hahahahahahahahahahahahahaha!!!
We need to call the ancient aliens back.... they could fix the levees...
I have always been amazed when People are surprised when "mother nature" wins. NOLA is a prime example.. and so is Holland & the Sacramento valley.
We seem to be under the impression that we can do what we wish where we wish... yet are astounded when it fails.
You build a city below sea level.. and then scream blue murder about incompetence when it floods... go figure?
How much energy is in a Hurricane... or the Pineapple Express when it is really running.. can we even fathom that kind of power.. yet we figure we can tame it with steel and cement?
Doomed to failure every time.. its just a matter of when.. not if.
so why even bother with levees then, right?
Probably within the expectable lifetime of elementary school children.
Actually... if people had stuck to the initial lay of the land.. there would be no levees.
Instead they have tried to partition areas.. for commercial gain and farming.
So... all they are trying to do is change the way mother nature works... will it fail... eventually...yes.
so, how many cities do we lose without the levees?
You can't compare apples and oranges... if the levees were not there.. the cities would be some place else.
How much of NOLA will never be recovered now?
Don't ask me.... ask Pat.....
weatherboy....sorry, but that is incorrect....try again....
ahhhhhh.... nevermind.....
Tropical Cyclone Advice #3
TROPICAL CYCLONE ANTHONY (11U)
5:00 AM EST January 29 2011
=========================================
At 4:00 AM EST, Tropical Cyclone Anthony, Category One (999 hPa) located 16.1S 154.7E, or 910 kmeast northeast of Townsville and 810 km east northeast of Bowen.. has 10 minute sustained winds of 35 knots with gusts of 50 knots. The cyclone is reported as moving southwest 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: T3.0/3.0/W1.5/24HRS
Tropical Cyclone Anthony is currently slow moving. Anthony is expected to turn to the southwest during Saturday while gradually intensifying.
Damaging winds are expected to develop about coastal and island communities between Innisfail and St Lawrence during 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 153.6E - 35 knots (CAT 1)
24 HRS: 17.5S 152.1E - 45 knots (CAT 1)
48 HRS: 19.8S 147.2E - 55 knots (CAT 2)
72 HRS: 20.8S 141.7E - 20 knots (TROPICAL LOW)
Additional Information
=======================
Low DT implied by small curved band, but FT and CI held up due to constraints.
The next tropical cyclone advice on Tropical Cyclone Anthony will be issued at 1:00 AM UTC..
Tropical Cyclone Advice #39
SEVERE TROPICAL CYCLONE BIANCA (12U)
3:00 AM WST January 29 2011
=======================================
At 2:00 am WST, Severe Tropical Cyclone Bianca, Category Three (965 hPa) located at 26.2S 107.7E, or 620 km west southwest of Carnarvon and 1020 km northwest of Perth has 10 minute sustained winds of 75 knots with gusts of 105 knots. The cyclone is reported as moving south southwest at 13 knots.
Hurricane Force Winds
===================
25 NM from the center
Storm Force Winds
================
40 NM from the center
Gale Force Winds
=================
150 NM from the center in northeastern quadrant
120 NM from the center in northwestern quadrant
150 NM from the center in southern quadrant
Dvorak Intensity: T4.0/4.5/W1.0/24HRS
Severe Tropical Cyclone Bianca is weakening as it moves south southwest well away from WA mainland.
Bianca is expected to weaken further today and move in a southeasterly direction towards the southwest corner of the state. There is a risk that Bianca will maintain tropical cyclone intensity as it approaches the coast during Sunday. If this happens, coastal areas between Jurien Bay and Albany could experience DAMAGING WINDS with gusts to 120 kilometres per hour. Wind gusts to 100 kilometres per hour may be experienced through inland parts southwest of a line Jurien Bay to Albany.
On Sunday tides between Jurien Bay and Cape Naturaliste may rise significantly above the normal high tide mark with VERY ROUGH SEAS, DANGEROUS SURF and FLOODING of LOW LYING COASTAL AREAS. SIGNIFICANT COASTAL EROSION is possible. HEAVY RAINFALL is also possible on the southern side of the system. LOCALISED FLOODING is possible but extensive flooding is not expected.
VERY HIGH to SEVERE FIRE DANGERS are likely near the west coast on Sunday. EXTREME to CATASTROPHIC FIRE DANGERS are possible across inland areas south of a line from Geraldton to Leonora to Israelite Bay on Sunday.
Tropical Cyclone Warnings/Watch
================================
A Cyclone WATCH is current for coastal areas from Jurien Bay to Albany, including Perth, Mandurah, Bunbury and Busselton.
Forecast and Intensity
=======================
12 HRS: 28.9S 108.3E - 60 knots (CAT 2)
24 HRS: 30.9S 110.7E - 45 knots (CAT 1)
48 HRS: 32.9S 118.6E - 25 knots (TROPICAL LOW)
72 HRS: -- --- --
Additional Information
========================
Position based on IR and microwave. Dvorak intensity: last IR image shows collapse of the eye indicating DT=3.5 [curved band wrap of 1.0], however time averaged DT and MET plus weakening constraint holds FT at 4.0 and CI at 4.5. Mean winds estimated at 75 knots. Weakening is likely due to the cooler ocean temperatures [<26C] now that it is moving south of 26S.
Despite its southerly location, the shear remains low at 10 knots, but this should 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.
The next tropical cyclone advice on Severe Tropical Cyclone Bianca will be at 1:00 AM UTC..
Californians have already approved levee improvement bonds.
"A few old farmers tried to tell the state legislators in Sacramento but they were not heard because of the wildlife-loving people..."
I assure you that more than a few NorthernCalifornia farmers were less than happy about turning some of the world's most fertile land into a salt marsh for the sake of higher profits for a handful of SouthernCalifornia farmers, and lusher SouthernCalifornia lawns.
Similarly salmon fishermen didn't appreciate their catch being reduced to zero just to fill some more SouthernCalifornia swimming pools and to water some more SouthernCalifornia golf courses.
Can you imagine the reactions of Palin and her cronies if your government tried to do something?
You have to be very stupid to have a golf lawn in the middle of a desert.
You just have to read some of the comments on this blog
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