Storms fueled by atmospheric rivers have torn across California over the past month, producing historic amounts of rain and snow — with devastating effects.
“We haven’t seen this level of widespread impacts from storms across the state since the early 2000s,” said Chronicle Newsroom Meteorologist Gerry Díaz.
The recent series of storms has brought widespread flooding , destructive landslides , wind damage and coastal deterioration. The storms have caused at least 20 deaths.
Downtown San Francisco saw a deluge on New Year’s Eve, when 5.46 inches of rain fell in a 24-hour period.
“That makes it the second-wettest single day in the city’s history going back to the Gold Rush years,” Díaz said.
The flurry of storms has created the wettest 10-day period since 1998 at a number of sites across Northern and Central California, including Stockton, Oakland, Livermore Airport, Sacramento Airport, Modesto and downtown San Francisco.
The values on the charts add up rainfall amounts over 10 days for each location. The total for Oct. 10, for example, is the sum of rain that fell from Oct. 1 through Oct. 10. The current water year and the 2022 water year are highlighted above. Previous water years, since Oct. 1998, are in gray.
All this rain has meant that this water year San Francisco is far above the amounts collected in recent years. The city has already logged 21.75 inches of rain as of Jan. 17, not even one-third of the way through the current water year. By this time of year, San Francisco typically only sees 10.75 inches.
One of the wettest years in recent history was 2017, during which storms fueled by atmospheric rivers led to near catastrophe at Oroville Dam . While the dam ultimately held, repairs totaled over $1 billion.
This water year’s amount is still far shy of the 32.44 inches that fell in San Francisco in 2017. But the recent rain has made a sizable dent in California’s multi-year drought, though resolving long-term impacts of the drought — such as depleted groundwater levels — will require more sustained rain.
The chart also shows how California swings between dry and wet years. Scientists expect this pattern to become even more extreme due to climate change.
“That does mean, yes, more severe droughts on the one hand,” said Daniel Swain, a climate scientist at UCLA and the Nature Conservancy, at an online presentation last week. “But also more severe periods of extreme precipitation on the other — like what we're seeing now.”