Risk of California superstorm – and what should be done about it?

Human beings have a remarkable capacity to build settlements in harsh conditions. Recently, I have wondered what would possess settlers in the 1800s to live in the Upper Midwest with its harsh winters. A classic example of a place with both advantages and disadvantages: California. On one hand, a temperate to warm climate with a wonderful range of habitats (mountains to coast) and rich farmland in the middle of the state.

And yet, California has a number of natural threats. The latest: scientists predicting a superstorm that could flood the state for an extended period.

A group of more than 100 scientists and experts say in a new report that California faces the risk of a massive “superstorm” that could flood a quarter of the state’s homes and cause $300 billion to $400 billion in damage. Researchers point out that the potential scale of destruction in this storm scenario is four or five times the amount of damage that could be wrought by a major earthquake…

The threat of a cataclysmic California storm has been dormant for the past 150 years. Geological Survey director Marcia K. McNutt told the New York Times that a 300-mile stretch of the Central Valley was inundated from 1861-62. The floods were so bad that the state capital had to be moved to San Francisco, and Governor Leland Stanford had to take a rowboat to his own inauguration, the report notes. Even larger storms happened in past centuries, over the dates 212, 440, 603, 1029, 1418, and 1605, according to geological evidence…

The scientists built a model that showed a storm could last for more than 40 days and dump 10 feet of water on the state. The storm would be goaded on by an “atmospheric river” that would move water “at the same rate as 50 Mississippis discharging water into the Gulf of Mexico,” according to the AP. Winds could reach 125 miles per hour, and landslides could compound the damage, the report notes.

Such a superstorm is hypothetical but not improbable, climate researchers warn. “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,” Geological Survey scientist Lucy Jones said in a press release.

If this is a real possibility, the question then becomes what the state should do about it. It is another example of weighting risks: should the state implement all sorts of rules and plans to limit the possible damage or should they simply go on with life and deal with the consequences when they come? Of course, California isn’t the only place that faces such questions: hurricanes pose a similar threat on the East or Gulf Coasts and many communities have homes or businesses built on flood plains.

Regardless of what California does with this information, perhaps this can become additional fodder for disaster movies. I can see the plot line now: California is hit with a major storm followed by a major earthquake with both accompanied with major mudslides followed by our set of heroes running for the hills…you’ve seen this plot line before. But this flood of 1861-1862 does sound intriguing – perhaps more information about this past event would help current officials plan for future events.