Noah's Ark Has Nothing on This California Forecast

[crossthread]

credits.. By LORI PREUITT

http://www.nbclosangeles.com/news/local-beat/Noahs-Ark-Has-Nothing-on-This-California-Forecast-113643889.html

One of the biggest fears for most Californians is "the big one." Many of us expect to one day experience a major earthquake that will cause major calamity. We have a state agency filled with brilliant men and women who track even the smallest of quakes hoping to find a way to predict "the big one."

So you might be surprised that a group of 117 scientists who work for the USGS aren't talking about earthquakes today, and instead are warning us of something that could be even more destructive. The USGS unveiled Friday a new study of what they call an "Arkstorm Scenario." It's a mega-storm that would measure rain in feet instead of inches.

Playing off the Biblical story of Noah's ark, scientists say an Arkstorm is an every-other century occurrence. That might not be that far off once you look at the historical data. For the novice, it is a weather system that plants itself out in the Pacific Ocean and the "storm door" never closes. You can see the weather map in the below clip.

Arkstorm is a hypothetical scenario that describes a rainstorm that produces a 10-foot wall of water that could flood a swath of the state from the Yosemite Valley to the Pacific Ocean. A similar storm hit back in 1861 and left the central valley of California impassable.

Scientists didn't put a number in lives lost, but said it would leave in its wake destruction in the $300 billion range.

The scenario combines prehistoric geologic flood history in California with modern flood mapping and climate-change projections to produce a hypothetical yet plausible scenario. The purpose is to prepare state and federal officials to be ready to mobilize an emergency response.

Chief Arkstorm scientist Lucy Jones said their models show one in four homes would experience flood damage.

"We think this event happens once every 100 or 200 years or so, which puts it in the same category as our big San Andreas earthquakes. The Arkstorm is essentially two historic storms (January 1969 and February 1986) put back to back in a scientifically plausible way. The model is not an extremely extreme event," Jones said.

Unlike "the big one," a storm of this magnitude would take days if not weeks to become a reality. It's something meteorologists will have plenty to say about ahead of time.

[bobbutts]

Interesting stuff. Having lived in Tahoe for awhile, it's pretty incredible when the moisture lines up and 5'-10' of snow fall. I guess this is just a more extreme version of that.

Don't see much of a climate change connection though, they mentioned

The scenario combines prehistoric geologic flood history in California with modern flood mapping and climate-change projections

but didn't say if it increased the chances of this or juiced the storm more.

Picture how much snow this would be in the high sierra!

[ice1972]

Interesting stuff. Having lived in Tahoe for awhile, it's pretty incredible when the moisture lines up and 5'-10' of snow fall. I guess this is just a more extreme version of that.

Don't see much of a climate change connection though, they mentioned

but didn't say if it increased the chances of this or juiced the storm more.

Picture how much snow this would be in the high sierra!

Probably not much......this ArkStorm probably has a juicy subtropical connection that would raise snow levels significantly......I remember New Years Day 1997 driving up to Lake Tahoe during one of the Pineapple Connection storms California sees and it was raining heavily (I mean really heavy) all the up to Truckee and higher......the flooding was immense from all the snowmelt......anyway.....this is an interesting topic..

[bobbutts]

Probably not much......this ArkStorm probably has a juicy subtropical connection that would raise snow levels significantly......I remember New Years Day 1997 driving up to Lake Tahoe during one of the Pineapple Connection storms California sees and it was raining heavily (I mean really heavy) all the up to Truckee and higher......the flooding was immense from all the snowmelt......anyway.....this is an interesting topic..

Yeah, I moved there around 1998 and many people mentioned how big a deal the New Years flood was. I guess a big component of it was massive melt off, so I suppose this ark storm would unlock additional water from the snowpack by raining on it.

[vortmax]

It seems for this type of pattern were to become a reality (it's really not a single storm per say) it would take some major blocking. I wonder what type of blocking was in place for the 1861 event?

[stellarfun]

It seems for this type of pattern were to become a reality (it's really not a single storm per say) it would take some major blocking. I wonder what type of blocking was in place for the 1861 event?

From Wiki,

Prior to the flooding, Oregon had steady but heavier than normal rainfall during November and heavier snow in the mountains.^[3]

The weather pattern that caused this flood was not an El Nino, but from the existing Army and private weather records it has been determined that the polar jet stream was to the north as the Pacific Northwest experienced a mild rainy pattern for the first half of December 1861. Then the jet stream slid south and freezing conditions were reported at Oregon stations by December 25. Heavy rainfall began falling in California as the longwave trough moved down over the state, remaining there until the end of January 1862 and causing rain to fall everywhere in the state for nearly 40 days. Eventually the trough moved even further south, causing snow to fall in the Central Valley and surrounding mountain ranges.^[4]

http://en.wikipedia.org/wiki/Great_Flood_of_1862^Footnotes:

1. ^ ^{a b c d e} Lansing Wells, Edward (1947). "Notes on the Winter of 1861–2 in the Pacific Northwest". Northwest Science 21: 76–83. http://www.vetmed.wsu.edu/org_NWS/NWSci%20journal%20articles/1940-1949/1947%20vol%2021/21-2/v21%20p76%20Wells.PDF.
2. ^ Null, Jan; Hulbert, Joelle (January/February 2007). "California Washed Away: The great flood of 1862". Weatherwise. http://www.skagitriverhistory.com/PDFs/wwjan07.pdf. Retrieved 3 October 2010. p. 29

[stellarfun]

Minnesota weather 1862

Jan-Feb extremely cold.

http://www.climatestations.com/minneapolis/historical-writeups/minnesota-weather-for-1862.html

[aslkahuna]

The 1955 floods were a lesser version of 1861-62 and in fact were, for the Central Valley and Coastal CA down to Pt. Conception, the worst since 1861-62. The moisture stream was classic Pineapple and the Pattern featured a blocking High aloft that rolled over the backside of the strong Postive tilt trough extending from the PV over Canada to the West Coast with the axis across WA and then OR. South of the trough a massive Pacific jet extending back past HI brought tropical moisture into CA with the Z level rising to 10k. Surges of heavy rain occurred as imbedded impulses and their associated jet maxima moved into CA. Rainfall amounts ranged as high as 20+ inches in 24 hours and the coast ranges saw rainfall amounts in the 50-100 inch range. The San Lorenzo River in Santa Cruz CA rose nearly 40 feet in 2 hours sweeping away homes and house trailers. Every river, creek, dry wash, arroyo, drainage ditch and street gutter in Central and Northern CA including the Bay Area was in high flood. San Jose was cut off from the rest of the Bay Area by flooded highways and flooding spilt the city in two except for one high overpass. Our side of town was cut off for hours by flooded roads though we were on high ground. After 10 days the trough slid south and east and as in 1861-62 snow fell at low levels as it did so. The flood control system of the Sacrament River was strained to the max and only a levee break near Yuba City saved Sacramento. The flooding extended well into San Joaquin River watershed with the Merced River at high levels. The death toll from the 1955 floods was 78 and damage was estimated at 350 million 1955 dollars-a repeat of 1955 would be an extreme disaster and a repeat of 1861-62 would be an absolute catastrophe. Important to note that far more people and a far bigger area would be affected by a storm of even the 1955 magnitude than a big earthquake and the economic impact would extend well beyond the borders of the State in either case. Point to remember-in 1861-62, California's population was very small and in 1955 not even half of what it is now. Also important to note is that both the 1861-62 and 1955 events were NOT restricted to CA alone but included portions of the adjacent states even as far as UT.

Steve

[metalicwx366]

California's Central Valley Poised For Ark Storm California could easily become the next Australia in 2011. What experts are saying could dwarf the 1997 floods in comparison.

"A series of storms more powerful than Hurricane Katrina and more damaging than the "big one" earthquake could hit California in our lifetime, according to the U.S. Geological Survey."

KCRA Channel 3 Sacramento reported on last nights 11 o'clock news, virtually forecasting an impending flood that could easily be the nations largest national disaster.

"I think Californians should be worried about this," USGS Director Marcia McNutt said.

Federal and state scientists and emergency responders discussed during a two-day conference in Sacramento that computer models based on historical data suggest a looming catastrophic "ARkStorm" could inundate California with nonstop flooding.

Potential flooding could cause more than $300 Billion in damage and cause five times the damage of thee worst case scenario earthquake and leave more people homeless than Hurricane Katrina. and inflict at least $300 billion in damage. "It's a hypothetical, but it can happen and has happened before in 1861-62," Mark Jackon of the National Weather Service said. "Federal and state officials are hoping this information will motivate government agencies to began preparing for a worst-case ARkStorm to convince residents to purchase flood insurance and to spark the creation of a warning system similar to the rating scale used for approaching hurricanes." KCRA Channel 3 News remarked.

Is this internet hype or a possibiltiy?

[metalicwx366]

Apparently its going to hit this year. pfft whatever!

[Clifford]

Dams should help, at least preventing a mix of snow-melt and rain water, so in many senses, we will be much better off now than we were a century ago.

Lake Mead seems to be at a historic low.

http://www.arachnoid.com/NaturalResources/

I suppose I don't stress too much over these emergency scenarios, although it never hurts to invest a little in emergency early warming systems and emergency preparedness systems.

[aslkahuna]

Dams should help, at least preventing a mix of snow-melt and rain water, so in many senses, we will be much better off now than we were a century ago.

Lake Mead seems to be at a historic low.

http://www.arachnoid...turalResources/

I suppose I don't stress too much over these emergency scenarios, although it never hurts to invest a little in emergency early warming systems and emergency preparedness systems.

Lake Mead has nothing to do with flooding in California. We had plenty of Dams in 1955 yet we nearly lost Sacramento and did lose Yuba City among others. Dams only hold so much water, what we are talking about here involves very much more water. It's happened before and will happen again for sure but I'm not optimistic that we will engage in much preparedness. Americans tend to pooh-pooh such scenarios with an "i'll never happen attitude" and when it does instead of blaming their own stupidity for not being ready they look for someone else to blame and sue. In 1955, PG&E was sued because it was alleged that their cloud seeding program caused the heavy rain-the suits fail because PG&E had shut the program down a month prior.

Steve