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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Seems the Sun is continuing to not play as expected. The revisions keep coming. We could have new numbers next week again!
http://solarscience.msfc.nasa.gov/predict.shtml
That hardly has anything at all to do with the subject. You should care only about the data I'm presenting to you, not from WUWT, but from NCDC. WUWT created the graph, and that is all. Also, if you think I operate solely off of data from a couple of websites, then you are quite mistaken, and obviously have not read very many of my posts.
You apparently weren't reading very carefully. I said nothing about global snowfall. I was speaking of the recent talk of AGW causing more frequent and more severe snowstorms in the northeast United States. Data from NCDC contradicts the idea that winter storms are becoming more severe. This is reinforced because increasing population would tend to raise the NESIS over time, but it has maintained a fairly flat trend, indicating either no change in nor'easter severity, or a slight decrease.
"while severe storms have become more frequent (as evidenced by the NYC and Philly factoids), they're not as widespread as they used to be, so any one event is generally affecting fewer people overall."
This sentence itself is a contradiction. If NYC and Philly show an increase in the number of heavy snowstorms, then the density/frequency of such storms passing through those areas must also be increasing. Not only that, but given population growth, the idea that snowstorms have been affecting fewer people over time is pretty far-fetched. That said, Philly and NYC are also only two cities, and the NESIS considers the entire northeast region as a whole.
I think this storm may exceed expectations. Definitely not good for Australia.
FLASH FLOOD WARNING
ARC125-302300-
/O.NEW.KLZK.FF.W.0001.110130T2057Z-110130T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LITTLE ROCK AR
257 PM CST SUN JAN 30 2011
THE NATIONAL WEATHER SERVICE IN LITTLE ROCK HAS ISSUED A
* FLASH FLOOD WARNING FOR...
CENTRAL SALINE COUNTY IN CENTRAL ARKANSAS...
* UNTIL 500 PM CST
* AT 255 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
A THUNDERSTORM WITH VERY HEAVY RAINFALL 3 MILES SOUTH OF LAKE
NORRELL...OR 9 MILES NORTHWEST OF BENTON. RADAR WAS ESTIMATING
THAT AS MUCH AS TWO TO FOUR INCHES OF RAIN HAS FALLEN OVER
PORTIONS OF THE WARNED AREA IN THE LAST HOUR. THE STORM IS
MOVING VERY SLOWLY...AND THIS WILL ONLY AGGRAVATE THE FLASH FLOOD
THREAT. WHILE PRECIPITATION MAY TAPER OFF IN SOME AREAS DURING THE
WARNING PERIOD...IT WILL TAKE SOME TIME FOR ANY HIGH WATER TO
RUNOFF.
* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
BRYANT... LAKE NORRELL... HURRICANE LAKE...
GRAPE... CROWS... CONGO...
BLAND... AVILLA... RUBICON...
KENTUCKY... COLLEGEVILLE...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
DO NOT UNDERESTIMATE THE POWER OF FLOOD WATERS. ONLY A FEW INCHES OF
RAPIDLY FLOWING WATER CAN QUICKLY CARRY AWAY YOUR VEHICLE. TURN
AROUND... DONT DROWN!
&&
LAT...LON 3459 9245 3458 9279 3473 9281 3477 9255
3470 9255 3469 9250
$$
/57
Currently, my thinking is it will be at its max a SSHS Category 4 and probably a major by landfall.
Sure looks like it. Tiny little storm, but its got some pretty good echos with it and it's not moving!
Erm, the population factor in the scale is based on the 2000 census, for all the storms, so there is no increasing population / decreasing impact factor.
Not that I think the statistic has any merit anyway, but 2010 has the most events since 1954, and the last 1/3rd of the graph has about 1/2 of the total events, so a trend is there, albeit a totally meaningless one.
I don't think inferrals should be made for specific storms or storm amounts or cold snaps or warm snaps as being either proof or denial of a theory that is based on a 200 year timescale + possible lag.
You guys really don't get it do you. Why does everything have to immediately be thought of as evidence for or against a global theory. That was clearly not the point of my post. The idea here is to show that all these claims that every severe weather event that ever comes along is due to AGW are not necessarily well-founded. Some people's rationalizing of these processes is just weird, and many of their claims are flat wrong. The processes that caused the snow storms of last winter and this winter actually go against everything the IPCC has been preaching would occur. It's gotten to the point that whenever something bad happens, somebody runs their mouth about AGW being to blame and it is just accepted. I posted a media article where one such person was running their mouth, and I posted data to refute his assumptions. Whether this has any weight globally is entirely not the point.
True.
A couple of years ago the NY Times and Washington Post both were printing stories and lamenting about how "snow days" were now a thing of the past for kids. Then came last winter and they turned right around and started claiming that "climate change" was causing more severe and frequent snow storms.... Ya can't have it both ways...
I remember that story. They posted graphs of NYC annual snowfall decreasing with time and kids were forgetting how to sled. Now it's all about increasing snow.
Global Climate Change Indicators
National Oceanic and Atmospheric Administration
National Climatic Data Center
Many lines of scientific evidence show the Earth's climate is changing. This page presents the latest information from several independent measures of observed climate change that illustrate an overwhelmingly compelling story of a planet that is undergoing global warming. It is worth noting that increasing global temperature is only one element of observed global climate change. Precipitation patterns are also changing; storms and other extremes are changing as well.
How do we know the Earth's climate is warming?
Thousands of land and ocean temperature measurements are recorded each day around the globe. This includes measurements from climate reference stations, weather stations, ships, buoys and autonomous gliders in the oceans. These surface measurements are also supplemented with satellite measurements. These measurements are processed, examined for random and systematic errors, and then finally combined to produce a time series of global average temperature change. A number of agencies around the world have produced datasets of global-scale changes in surface temperature using different techniques to process the data and remove measurement errors that could lead to false interpretations of temperature trends. The warming trend that is apparent in all of the independent methods of calculating global temperature change is also confirmed by other independent observations, such as the melting of mountain glaciers on every continent, reductions in the extent of snow cover, earlier blooming of plants in spring, a shorter ice season on lakes and rivers, ocean heat content, reduced arctic sea ice, and rising sea levels.
Global Climate Change Impacts in the United States: Report Home Page
The most comprehensive, authoritative report on Global Climate Change Impacts in the United States was released on Tuesday June 16th, 2009. This report presents, in plain language, the science and impacts of climate change on the United States, now and in the future. It focuses on climate change impacts on U.S. regions and various aspects of society and the economy such as energy, water, agriculture, and health. A comprehensive series of web-pages were developed that highlight the findings and major conclusions of the report and contain complete downloadable files of the report, as well as a host of additional content on climate change impacts on the U.S.
and B) the main reason I posted was that a) you were assuming stuff about population affecting the statistic, when they just appear to use the 2000 census (Link.
and
C) you also claimed no trend. There is a trend for an increased number of events from around 1995 - 2010, culminating in 2010 having the most events in the statistic, 4. However meaningless the trend is, it's still important not to claim there isn't one, a more accurate way would be to total them up and say there's a trend, but it's likely not significant.
sue me for trying to turn you into a scientist, which is afaik what you want to be. :)
For everyone's information, there is in fact no significant trend in frequency of severe winter storms in the northeast U.S. based off of the NESIS data. 2010 has a record number of them (4), though one year hardly constitutes a trend of any kind, and 2010 is fairly easily explained by the record low Arctic Oscillation that we've had for the last two winters.
Why don't you all stop trying to teach anything to these youngsters - they know everything already!
Just ignore them - I assume one day they will grow up
Oh, and a perfect example:
"Any would-be scientist who wants to be taken seriously should really stop reading WUWT--or at least stop using it as a primary teaching tool... ;-)"
Nothing more than an unfounded, snide remark intended to ruffle the feathers of any objective persona. No objective person is going to look to, nor fully agree with, any single point of view or any one blog.
Tell that to the people in the Northeast. I am sure they would love to hear it.
Snide? Perhaps--but if so, it's a snideness born of endlessly wading through the anti-science blather put out by such sites. But unfounded? Definitely not. Outside the denialist community--that is, out in the real world, among credible scientists--Watts' dishonest tactics and attempts at smear are well-known.
This data did not come from Watts. You're picking on the URL of a random image created to visualize the data. Check out the nice graph I posted above, made by me instead of Watts.
On 4th and 16 always.
Tropical Disturbance Advisory #7
TROPICAL CYCLONE YASI (09F)
6:00 AM FST January 31 2011
=================================
At 18:00 PM UTC, Tropical Cyclone Yasi, Category One (987 hPa) located at 13.6S 165.9E has 10 minute sustained winds of 45 knots. The cyclone is reported as moving west southwest at 13 knots. Position POOR based on multispectral enhanced infrared radar imagery with animation and peripheral surface observations.
Gale Force Winds
================
150 NM from the center in eastern semi-circle
60 NM from the center in southwestern quadrant
Overall organization has improved significantly past 24 hours. Convection increased past 6 hours. Primary band trying to wrap around the low level circulation center. System lies under an upper diffluent region in a weak sheared environment. CIMSS indicates decreasing shear along forecast path. Outflow good. Sea surface temperature is around 30C. System is expected to be steered westward b an easterly deep layer mean flow.
Dvorak assessment based on 0.60 LOG10 wrap yielding DT=3.0, MET=3.0, PT=3.0
Dvorak Intensity: 3.0/3.0/D1.0/24HRS.
Global models are developing Tropical Cyclone YASI further and maintaininga westward track.
Forecast and Intensity
=======================
12 HRS: 13.8S 162.9E - 55 knots (CAT 2)
24 HRS: 14.2S 159.7E - 60 knots (CAT 2)
48 HRS: 16.1S 153.6E - 65 knots (CAT 3)
The next Tropical Disturbance Advisory from Fiji Meteorological Services will be issued at around 2:30 AM UTC..
SH112011 - Tropical Cyclone YASI
Enhanced Infrared (IR) Imagery (4 km Mercator)
Time of Latest Image: 201101302132
A maturing Cyclone in the Southern Hemisphere.
Man may or may not be responsible for the warming of temps we have been experiencing. However, there are lots of other ways in which man has been modifying our planet that at least potentially have the possibility of modifying climate, at least on a regional scale. And, as we have become more and more aware over time, teleconnections rule; there's every likelihood that a regional shift in one part of the planet can and does impact climate shift elsewhere.
I keep saying, less name-calling and infighting about the facts, and more investigation thereof would be to everyone's benefit. If nothing else, it's a waste of time building tropical wx models that can't be depended on because la nina impacts or AO / NAO patternsof previous cycles can't be used as predictive scenarios for future events....
LOL
"Punt" is what deniers of a Warming Planet do.
Wheres Wisconsin?
Are they in the SEC ?
Again, I never said it did come from Watts; I merely mentioned the ridiculous frequency with which some visit such sites, and the even more ridiculous frequency with which some quote from them.
I guess the bottom line is this:
1) As Dr. Masters stated, five of New York City's top-ten snowfalls of the past 142 years have occurred in the past decade, and four of Philadelphia's all-time top ten snowfalls have occurred in a little over a year.
2) According to the NESIS data, there has been no significant increase in large severe snowfall events in the Northeast.
These two facts aren't mutually incompatible, are they?
Agree to disagree, fellas, and lets talk about the peak of the Southern hemisphere season instead....
No, Wisconsin is in the Midwest.
Which had nothing to do with my post, so you needn't have brought the issue up. We can avoid such rabbit trails if you confront only my data next time. Thank you.
TYVM,....
Whether the person on the other side of the debate with me will ever believe a word I say or not, perhaps what I post will resonate with some of the lurking readers and prod them to think carefully about the issues and research for themselves and look at this stuff. Such issues are what this blog is about during the winter, as unfortunate as it is. Dr. Masters himself is bold in putting forth literature on the subject.
Atlantic hurricane season will be here soon enough.
Global Climate Change Indicators
National Oceanic and Atmospheric Administration
National Climatic Data Center
Many lines of scientific evidence show the Earth's climate is changing. This page presents the latest information from several independent measures of observed climate change that illustrate an overwhelmingly compelling story of a planet that is undergoing global warming. It is worth noting that increasing global temperature is only one element of observed global climate change. Precipitation patterns are also changing; storms and other extremes are changing as well.
How do we know the Earth's climate is warming?
Thousands of land and ocean temperature measurements are recorded each day around the globe. This includes measurements from climate reference stations, weather stations, ships, buoys and autonomous gliders in the oceans. These surface measurements are also supplemented with satellite measurements. These measurements are processed, examined for random and systematic errors, and then finally combined to produce a time series of global average temperature change. A number of agencies around the world have produced datasets of global-scale changes in surface temperature using different techniques to process the data and remove measurement errors that could lead to false interpretations of temperature trends. The warming trend that is apparent in all of the independent methods of calculating global temperature change is also confirmed by other independent observations, such as the melting of mountain glaciers on every continent, reductions in the extent of snow cover, earlier blooming of plants in spring, a shorter ice season on lakes and rivers, ocean heat content, reduced arctic sea ice, and rising sea levels.
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