At least one person died, more than 1,000 prison inmates were evacuated from a county jail, and a levee broke amid flooding on New Year’s Eve in Northern California. A so-called “atmospheric river” brought more than five inches of rain to downtown San Francisco on December 31, making it the second wettest day in over 170 years of record keeping in the city. Elsewhere in the Bay Area rainfall totals exceeded four inches.
The New Year’s Eve atmospheric river was the second major precipitation event to sweep through West Coast states last week. An earlier storm led to at least five deaths in Oregon, all related to car crashes, reported The New York Times. Combined, the storms flooded creeks, rivers, roadways, and buildings. All that rain triggered landslides. In their wake, the atmospheric rivers left debris covered highways, sinkholes, power outages, and other damaged infrastructure.
Now, another major atmospheric river—likely to be the largest of the three—is forecast to bring much more rain to California. The National Weather Service is predicting widespread rainfall of 3 to 6 inches across the state from Wednesday to Thursday. In northern California and the coastal mountain ranges, rainfall could locally exceed those amounts. “Recent rainfall has left soils saturated and susceptible to flooding and rapid runoff concerns. Sensitive terrain will also have the potential for landslides,” NWS wrote.
Along with the rain, heavy winds up to 70 mph are forecast in some coastal areas. And, in the high Sierras Nevada mountains, snow will fall instead of rain—at possible rates of up to three inches per hour, causing white out conditions.
“To put it simply, this will likely be one of the most impactful systems on a widespread scale that this meteorologist has seen in a long while,” a Bay Area NWS meteorologist said in a Monday night forecast discussion. “The impacts will include widespread flooding, roads washing out, hillside collapsing, trees down (potentially full groves), widespread power outages, immediate disruption to commerce, and the worst of all, likely loss of human life,” that forecast continued. “This is truly a brutal system that we are looking at and [it] needs to be taken seriously,” the meteorologist concluded.
Though California and the rest of the West have been in dire need of water, suffering from extensive and significant drought, when so much rain falls all at once, it inevitably causes problems. Parched soils don’t readily absorb water, so most of it quickly becomes run-off. Burn scars from wildfire compound the issue—as scorched soil is even less absorbent. Together drought, recent fires, and heavy rain is a recipe for rock and mudslides—which closed roads around Northern California over the weekend.
Preparation for the oncoming storm has already begun, as clean-up from the previous storm continues. People around the Bay Area were filling sandbags to place around their homes and businesses on Tuesday—during a brief lull between rains.
Though atmospheric rivers are a common phenomenon in the West, and are responsible for most of California’s rain—some research suggests they are becoming more intense and frequent as climate change worsens. Click through to see a glimpse of the damage California is already dealing with.