However, for reasons specific to California, El Nino can present its own challenges to the Golden State. Five extra inches of rain spread over a year can help ease drought concerns, but can have disastrous effects if it all falls in just a matter of weeks or even a few months.
First, California is not flat. It's more susceptible to landslides than places like Texas and Oklahoma.
In 1982, more than 30 people died when 18,000 landslides ripped through the San Francisco region, destroying more than 7,000 homes and businesses and causing nearly $1 billion in inflation-adjusted damage. Thousands more landslides rolled through the same region in 1998, causing $200 million in damage, according to some estimates.
Those two years were particularly strong events—the only ones in history to be categorized as "very strong," meaning they created ocean temperature that were at least 2 degrees centigrade above seasonal averages.
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Tim McCrink, supervising geologist at the California Geological Survey, said the connection between rainfall and landslides has repeated itself over time.
"The correlation between rainfall and landslides is pretty solid," he said. "They can be caused by earthquakes too, but you won't have landslides without the rainfall."
Second, wildfires exacerbate the threat presented by landslides, and California has entered wildfire season.
McCrink distinguished between the more dangerous, quick-striking landslides caused by debris flow in flash floods, and the slower moving, deep-seated landslides that develop over longer periods of rainfall.
The threat of rainfall-induced debris flows becomes even more dangerous after wildfires, to which much of California remains particularly susceptible—largely due to the drought.