Dozens of atmospheric rivers hit the West Coast this winter and California snowpack levels are soaring.
California’s Department of Water Resources conducted its April snowpack survey on Monday and found that statewide levels are more than double the average for this month. Researchers at Phillips Station near Lake Tahoe recorded a snow depth of over 10 feet.
Usually, these surveys are conducted starting in January and end in April, the month where snowpack typically is at its peak. DWR director Karla Nemeth said the department plans to do an additional survey in May.
“The last time we did a snow survey in May was in 2020, and I think we had about an inch and a half of snow,” Nemeth said. “So you really get a sense of the extreme nature of our climate here in California.”
This month’s results aren’t shocking: During last month’s snow survey — taken on March 3, before another series of atmospheric rivers hit the state — DWR employees measured statewide snowpack levels nearly 200% higher than what’s expected for March.
Researchers agree that this wet winter isn’t completely unusual. California is often called a land of extremes, where a batch of drought years is frequently interrupted by an extremely wet one.
But Andrew Schwartz, lead scientist at UC Berkeley’s Central Sierra Snow Lab, said this winter has still been record-breaking. Officials say this winter is the fourth wettest on record.
“For anybody that's worked here in the last 70 years, this would be the number one season they've ever experienced,” he said. “That’s pretty unique.”
Research shows that atmospheric rivers will become more intense over time — that is, bigger storms with more precipitation — because of climate change. But wetter wet years doesn’t necessarily mean more snowpack.
Ruby Leung, an atmospheric scientist at the Pacific Northwest National Laboratory, said snowpack will likely peak before April in coming years as atmospheric rivers typically bring warmer precipitation. So instead of more precipitation meaning thicker snowpack, Leung said it can have the opposite effect.
“Actually [during] years when you have more atmospheric rivers, the April 1st snowpack is generally lower, which means you don't get enough snowmelt for the summertime when you really need it,” she said.
Leung said researchers like herself are working to better understand atmospheric rivers with the hope that at some point, they’ll be able to predict a wet season like this one months in advance. That could help California and other states better manage resources and prepare for intensely stormy weather. But for now, she said it’s important that states like California learn to manage their resources based on what the state already knows.
“Snowpack is so important — it’s a natural storage for water,” she said. “But we are really at risk of losing [it] fast because of the warmer temperatures, so I think this is something we wanted to recognize and prepare for.”
Next year, Schwartz said the lab will have new instrumentation installed, allowing researchers like himself to get more exact measurements for things like wind speed and the amount of snowpack evaporation. They’ll also install a real-time “hemispheric camera,” which will offer 360-degree views of the site and allow people to check its weather conditions online.
He added that it’s unlikely California’s next winter will be as wet as this one.
“Seeing as how we've had the second snowiest year on record here at the snow lab, the odds are that it'll be drier,” he said.
But he said it’s important to remember how quickly conditions can change in California, and to plan accordingly.
“Only seven short months ago we were talking about record lows in our reservoirs and entire communities going dry and having to truck water in,” he said. “Nature has given us this gift of an enormous snowpack and good rainfalls this year, and we shouldn't be ones to squander it.”
Officials say there’s a high risk of flooding in parts of the state, especially in the Central Valley, as the snowpack begin to melt in warmer months. They plan to keep an eye on vulnerable areas and will release information related to runoff in coming weeks.
