On Wednesday, San Jose Mercury News photojournalist Karl Mondon spotted a man in flooded Guerneville, California rowing through town in a blue dumpster.
A potent atmospheric river — a long band of water vapor that often transports ample amounts of moisture to the western U.S. like “rivers in the sky” — deluged portions of Northern California this week. The Russian River, which winds through the Sonoma County town of Guerneville, reached over 45-feet high and swamped the area, prompting the Sheriff to announce on Twitter that the town had been surrounded by water — with no way in or out.
While California relies heavily on these wintertime atmospheric rivers for its water, scientists expect these storms to grow wetter as Earth’s climate heats up.
“We’re likely to see rain in increasingly intense bursts,” Daniel Swain, a climate scientist at the National Center for Atmospheric Research, said in an interview.
“This really was a firehose aimed at Sonoma County,” Swain added.
Though it can be challenging to attribute any particular blast of rain to extreme weather stoked by climate change, this destructive event does have a telltale climate fingerprint.
“It does seem to be another data point suggesting individual atmospheric rivers are becoming wetter,” said Paul Ullrich, a climate scientist at the University of California at Davis.
“This year is exemplary,” said Ullrich, noting that atmospheric rivers dumped excessive amounts of rain in California during January. “It very much supports that hypothesis.”
Once heavy rains repeatedly hit California, they set the stage for floods. The ground becomes oversaturated with water.
“That sets up the whole system to overflow,” said Ullrich.
Future atmospheric rivers are expected to bring loads of water from both the tropics and drier areas over the ocean, said Swain. Due to simple physics, as the atmosphere warms, the air is able to hold more water vapor. Specifically, for every 1 degree Celsius (1.8 degrees Fahrenheit) of warming, the air can hold seven percent more water.
The forecast for the Russian River at Guerneville remains at 46’ by tomorrow night. That’s a disastrous amount of water for the town.
Thanks @gdimeweather for building this inundation product to visualize the pending flood reach. pic.twitter.com/szm7zGi4uo
— Jim Cantore (@JimCantore) February 27, 2019
On Tuesday, a National Weather Service station in the California city of Santa Rosa broke its record for daily rainfall.
“That’s a pretty impressive statistic,” said Swain.