California Superstorm Fact or Fiction?

California Storm

A new report about a so-called superstorm that could devastate California in the future is getting a lot of attention in the meteorological blogosphere.

The premise of the report, which was released last week, says a superstorm could develop that could last more than a month and dump up to 10 feet of rain on the state!

A group of 117 scientists, engineers, lifeline operators, emergency planners and insurance experts worked for two years on the report. They used computer models analyzing the impacts of two storms that soaked California in 1969 and 1986.

The Weather Channel’s Severe Weather Expert Dr. Greg Forbes (Find him on Facebook) weighed in on the report.

“I certainly agree with the sense that California could get a storm worse than what we’ve seen in our limited period of record, but the 125-mph wind speed would likely not affect a very large area and the rainfall amounts seem too extreme,” says Dr. Forbes.

Atmospheric river

Courtesy: AP/National Weather Service

Scientists say the so-called superstorm would be fed by an “atmospheric river,” which is essentially a huge hose-like flow of moisture from the Pacific Ocean into California.

Dr. Forbes points out that this report portrays a worst-case scenario. He says this realistically could happen once or twice a millenia. The Weather Channel did an episode of “It could Happen Tomorrow,” that focused on a storm that could overwhelm the levees in the Sacramento Valley and again turn the area into an inland sea, as a storm did in 1861-1862.

Possible Effects of So-Called California Superstorm

  • Overwhelm state’s flood protection system
  • Cause massive flooding
  • Touch off hundreds of landslides
  • Result in serious damage in state’s major population centers

“We create these scenarios to understand what are the implication of the types of very rare events that science tell us has to happen in our future,” Lucy Jones, chief scientist of the USGS Multi-Hazards Demonstration Project, said following a symposium with the researchers at the University of California, Davis.

Jones said geological records show superstorms happened numerous times in the past, with the same frequency as a big earthquake striking the San Andreas Fault.

This project, called the “ARkStorm” project, resulted in the first statewide map detailing areas susceptible to landslides. Scientists also created a modeling system for analyzing severe storm impacts to coastal areas, and a scaling system to categorize the intensity of atmospheric rivers — the force behind most winter storms over California.

Scientists say historical records show California has had several storms in which 16 inches of rain fell in three days — the same amount left in the wake of hurricanes over Gulf Coast states.

“Our storms really are as bad as hurricanes in the amount of rain that they can bring,” USGS Director Marcia McNutt said. “Without that type of labeling, we haven’t recognized that our storms are that bad and we risk underestimating emergency response (to storms).”

The Associated Press contributed to this report.

SOURCE: weather.com

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