Storms refresh lagging snowpack, more rain on the way
California ushered in the New Year with a dry and disappointing snowpack in the Sierra Nevada — just 25% of the historical average.
But in the month since, the picture has improved significantly. On Monday, the snowpack, a 400-mile frozen reservoir that provides nearly one-third of the state's water supply, had jumped to 52% of normal, boosted by several big storms that have taken ski resorts out of the doldrums in recent weeks and tempered talk of a 2024 “snow drought.”
“We've come a long way from where we were at the beginning of the month,” said Andrew Schwartz, lead scientist at the UC Berkeley Central Sierra Snow Laboratory near Donner Summit west of Lake Tahoe.
Between Oct. 1 and New Year's Day, just 35 inches of snow fell at the UC snow lab site, off Interstate 80. On Monday, that seasonal total had grown to 105 inches. For that location, at nearly 6,900-feet elevation, Monday's total is 61% of the historical average — a number that while below normal is expected to grow in the coming days.
“There's still some hope we are going to see a wetter pattern the first few weeks of February,” Schwartz said.
California's water officials today will tromp out to Phillips Station near Sierra-at-Tahoe ski resort to take their second monthly manual snowpack reading of the season — a largely ceremonial event in an age when snow gauges across the Sierra provide digital readings every day.
A significant storm system is forecast to hit Northern California and the Sierra tonight through
Friday, with chances of another rolling in Sunday and next Monday.
“It will be on the higher side of the storms we've seen this year,” said Katrina Hand, a meteorologist with the National Weather Service in Sacramento. “You could see ponding of water on the roads this week, some creeks rising to near flood stage. And it will bring more snow to the Sierra.”
The storm, an atmospheric river from Hawaii that is expected to be a 2 on a scale of 1 to 5 — with 5 being the strongest — is forecast to dump 1 to 3 inches of rain across much of the Bay Area by Friday.
By Friday, the storm is forecast to bring up to 2 feet of new snow to the Lake Tahoe area, up to 3 feet farther south at Sonora Pass, and up to 5 feet on Mount Lassen.
California often experiences big swings in the amount of rain and snow it receives each year.
“Every winter, water managers are biting their nails and investing in Pepcid,” said Felicia Marcus, a visiting fellow at Stanford University's Water in the
West Program. “The start to this winter was anemic, but right now it's pretty OK.”
As the Earth continues to warm from climate change, scientists say that California is seeing more “weather whiplash” between very dry and very wet years. Eight of the past 12 years have been drought years in the state, punctuated by some drenching years in 2017 and 2023.
Last year, a series of huge atmospheric river storms battered California, ending the state's severe 202022 drought. Last Feb. 1, the Sierra snowpack was a staggering 212% of normal. By April 1, it was the biggest snowpack in 40 years, at 232% of the historical average. A few ski resorts stayed open until the Fourth of July last year.
The fact that this year has begun much more modestly is in many ways a good thing, experts said Monday.
Reservoirs around the state filled last year because of the relentless rain and in many places are still above average for this time of year. If this winter had started with a new series of big atmospheric river storms, it could have filled them to the top, causing flooding downstream.
“You don't want to fill them up this time of the season, because if the storms come in faster than you were expecting, then you have a flood risk,” Marcus said. “Droughts are bad, but floods kill people.”.
Unless all the rain and snow turns off completely starting in mid-February, California should be in decent shape from a water supply standpoint this summer, experts said Monday, with the chances of urban water restrictions low.