State water surveyors who trekked into the Sierra Nevada on Wednesday found exactly what they expected: little snow and long odds of anything but a dismally dry year ahead.
Despite last week’s pounding snowstorm, which hammered roads with days of whiteouts and delivered ski slopes as much as 10 feet of fresh powder, this month’s statewide snowpack measured just 70% of average.
The reading was better than a month ago, when the gauges read a paltry 52% of average. But the bump, while big, still leaves California water managers unlikely to meet everyone’s needs in the coming year.
Mountain snow makes up nearly one-third of the state’s annual water supply. Cities and farms are heavily dependent on the giant reservoirs that catch the melt-off from the towering Sierra and southern Cascades. With two of the three wettest months of the year now passed, little time remains for the snow season to rebound.
“We have to prepare for the dry year that’s going to be here,” said Jay Lund, co-director of the Center for Watershed Sciences at UC Davis and a professor of engineering. “And it’s going to be the second dry year, so it means things are going to have to be a little tighter.”
Lund and other climate experts say the probability of below-average seasonal precipitation this year is above 80% for much of the state.
The operators of California’s state and federal water projects, who oversee dozens of reservoirs, have already told their customers to plan on fewer water deliveries come spring and summer. As of Tuesday, the state’s largest reservoir, Shasta Lake, contained 69% of the water it typically has this time of year, while Lake Oroville, the second-largest reservoir, contained 54%.
While most urban water suppliers have reserves to get them through back-to-back dry years, many farmers and wildlife managers don’t. Growers have begun thinking about which crops to cut back on while administrators of animal refuges and fish restoration programs are figuring out how they’ll get by with limited supplies.
Dry years are common in California. But scientists say the changing climate is exacerbating the extremes, so drier periods are becoming even drier. And once a dry period takes hold, it becomes that much harder to shake, meaning already the odds for 2022 are leaning toward more of the same.
“Next year we’ll start off with less groundwater and less base levels in the streams,” Lund said. “It will take that much more precipitation to get the same amount of runoff.”
The snow survey team with the Department of Water Resources visited Phillips Station off Highway 50, south of Lake Tahoe, on Wednesday morning, a monthly wintertime ritual that dates back to World War II.
While the Sierra Nevada and southern Cascades have since been fitted with dozens of sensors to track the snowpack remotely, the state’s five yearly visits to Phillips Station continue a longstanding data set that serves as an additional eye on California’s frozen water reserve.
The crew found a higher level of snow at the site, at about 6,800 feet above sea level, than at most measurement stations, because of a particularly strong storm showing in the area. Snow depth was 63 inches, which translates to 17 inches of water, or 93% of average for early February.
Meanwhile, the state’s cumulative read of its sensors pegged snowpack across the entire central Sierra, which includes the Tahoe region, at 74% of average. The southern Sierra stood at 57% of average while the northern Sierra and southern Cascades stood at 69% of average.
“While we saw a very strong atmospheric river last week, it was just one storm and it doesn’t make up for how dry we were from October through December,” said Chris Orrock, spokesman for the Department of Water Resources.
Like many urban water suppliers, the East Bay Municipal Utility District, which provides water to 1.4 million Bay Area residents, is monitoring the water situation closely. The agency is waiting until the traditional end of the snow season, in April, before making any decision on whether to ask customers to conserve a bit more.
“It’s still early enough. We still have some time,” district spokeswoman Andrea Pook said. “But it’s always smart to use water wisely. It’s a good time for people to assess their indoor water use. It’s also a good time to consider your outdoor landscape.”
Kurtis Alexander is a San Francisco Chronicle staff writer. Email: kalexander@sfchronicle.com Twitter: @kurtisalexander
February 04, 2021 at 02:42AM
https://www.sfchronicle.com/environment/article/Despite-recent-storms-California-s-dismal-snow-15922027.php
Despite recent storms, California’s dismal snowpack fuels concern about dry year ahead - San Francisco Chronicle
https://news.google.com/search?q=dry&hl=en-US&gl=US&ceid=US:en
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