Noah’s Ark Has Nothing on This California Forecast

The "ArkStorm Scenario" would bring more calamity than major earthquake

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.

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