Preparing For Frankenstorms: “The most powerful low pressure system in 140 years of record keeping” slams the Southwest.
[Via Climate Progress]
This is a guest repost from Wonk Room’s Brad Johnson. I may need to add a new category — uber-extreme weather. The anti-science crowd has been strangely silent about this uber-storm, though they love to tout cold snaps as evidence of nonexistent global cooling (see “Disinformers to media: Please make case for something that isn’t true using data we don’t believe“). For more on the records set by this story, see Capital Climate’s “Strong Pacific Coast Storm Breaks Rainfall, Low Pressure Records.”
The “strongest winter storm in at least 140 years,” swept through the Southwestern United States last week, “bringing deadly flooding, tornadoes, hail, hurricane force winds, and blizzard conditions.” Rain dumped on Los Angeles, San Diego, and Phoenix, as mountains received up to four feet of snow. Wind gusts exceeding 90 miles per hour, tornadoes, and water spouts spun off the monster storm. Over 159,000 people lost power in the storm’s wake. Meteorologist Dr. Jeff Masters wrote on Friday that the storm was “truly epic”:
We expect to get powerful winter storms affecting the Southwest U.S. during strong El Niño events, but yesterday’s storm was truly epic in its size and intensity. The storm set all-time low pressure records over roughly 10 – 15% of the U.S.–over southern Oregon, and most of California, Nevada, Arizona, and Utah.
“California has been pounded by a series of winter storms and rains,” said Gov. Arnold Schwarzenegger during a news conference in Los Angeles. “The storms brought wind gusts of up to 80 miles [an hour] across the mountains and the canyons, major highways and roads were closed, flights have been grounded, thousands of homes and businesses lost power, more than 2,100 homes were evacuated. Sadly and unfortunately, some people lost their lives.”
[More]
One of the most powerful storms recorded since the tremendous storms seen 140 years ago (Check out the CIMSS Satellite Blog for some great pictures from space]. These are the lowest pressures ever seen in most of this area. This is more than just once in a lifetime. This was quite an extreme weather event.
The worry is that California could be hit by a similar sort of storm series seen in 1869.
Beginning on Christmas Eve, 1861, and continuing into early 1862, an extreme series of storms lasting 45 days struck California. The storms caused severe flooding, turning the Sacramento Valley into an inland sea, forcing the State Capital to be moved from Sacramento to San Francisco for a time, and requiring Governor Leland Stanford to take a rowboat to his inauguration. William Brewer, author of “Up and down California,” wrote on January 19, 1862, “The great central valley of the state is under water—the Sacramento and San Joaquin valleys—a region 250 to 300 miles long and an average of at least twenty miles wide, or probably three to three and a half millions of acres!” In southern California lakes were formed in the Mojave Desert and the Los Angeles Basin. The Santa Ana River tripled its highest-ever estimated discharge, cutting arroyos into the southern California landscape and obliterating the ironically named Agua Mansa (Smooth Water), then the largest community between New Mexico and Los Angeles. The storms wiped out nearly a third of the taxable land in California, leaving the State bankrupt.
The 1861-62 series of storms were probably the largest and longest California storms on record. However, geological evidence suggests that earlier, prehistoric floods were likely even bigger. There is no scientific evidence to suggest that such extreme storms could not happen again. However, despite the historical and prehistorical evidence for extreme winter storms on the West Coast, the potential for these extreme events has not attracted public concern, as have hurricanes. The storms of 1861-62 happened long before living memory, and the hazards associated with such extreme winter storms have not tested modern infrastructure nor the preparedness of the emergency management community.
The area has had lots of planning dealing with earthquakes but not for another series of storms like this. They refer to this as an Atmospheric River storm with a value of 1000, where copious amounts of water from the tropics is translocated to California. We are talking about 8 feet of rain in the Central Valley.
The term atmospheric river is really quite visual. Here is a nice picture from one in 2004
(from NOAA).
You can see the nice finger that reaches out to the West Coast. When the moisture hits the mountains, huge amounts of rain fall. The unstable air produces what looks very much like a hurricane, although the actual physical causes are different.
But the latest AR storm California is dealing with follows another one from October, where 21 inches of rain fell in 24 hours as Big Sur was whipped by hurricane force winds.
This not just a California phenomenon. The picture below demonstrates an atmospheric river hitting the Pacific NW. If we had 8 feet of rain in 40 days, I think most of us would be washed to the sea. Just an inch or two produces large amounts of flooding. Our valleys are not as huge as California’s is.
Of course, we heard all about the cold on the East Coast but what about all the water and storms on the West Coast?
