On the 17th anniversary of the Northridge earthquake, it seems like a good time to point out the new research that says a theoretical Pacific-spawned superstorm is now believed likely to do much more damage in California than a major earthquake on the San Andreas Fault. Lucy Jones, the U.S. Geological Survey scientist that most in SoCal know as a quake specialist, is chief scientist of the USGS project that is publicizing the potential threat. Like the forecast of a Big One on the San Andreas, the storm scenario is based on analysis of past events.
The scenario, basically, is akin to two of the biggest storm cycles of the past half-century occurring back to back — 40 days of rain dropping as much as ten feet of water, fed by a massive "river" of tropical moisture in the atmosphere that lodges over the state. Very high winds, landslides and widespread flooding are part of the model, with damage possibly reaching $300 billion as systems for channeling storm water become over-matched.
Marcia K. McNutt, the director of the geological survey, said that 150 years ago, over a few weeks in the winter of 1861-62, enough rain fell to inundate a stretch of the Central Valley 300 miles long and 20 miles wide, from north of Sacramento south to Bakersfield, near the eastern desert.
The storms lasted 45 days, creating lakes in parts of the Mojave Desert and, according to a survey account, “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 Gov. Leland Stanford to take a rowboat to his inauguration.”
It was after heavy rainfall and flooding in 1938 that inundated Los Angeles that the L.A. River and other big drainages were channeled in concrete and flood control projects such as Hansen Dam and Sepulveda Dam were quickly built.
Because I hadn't run this yet, watch (and listen) as rising flood waters in Australia clear out a parking lot last week.