This photo provided by Mammoth Mountain Ski Area shows snow falling around the lodge and chairlift on Monday, Jan. 22, 2024, in Mammoth Lakes, California. (Christian Pondera/Mammoth Mountain Ski Area, via AP)
California started the new year with a dry and disappointing snowpack in the Sierra Nevada, only 25% of the historical average.
But in the month since then, things have improved significantly, as have the stock market and 49ers playoff expectations. On Monday, a vast 400-mile-long frozen reservoir that supplies nearly a third of the state's water supply was destroyed in the wake of several major storms that have brought ski resorts out of the doldrums in recent weeks. Snowfall has jumped to 52% of normal levels, and mild talk about a “snow drought” in 2024.
“We've come a long way from where we were at the beginning of the month,” said Andrew Schwartz, chief scientist at the University of California, Berkeley's Central Sierra Snow Laboratory near the summit of Donner Mountain on the west side of Lake Tahoe.
Between Oct. 1 and New Year's Day, only 35 inches of snow fell at the UC Snow Lab site along Interstate 80. On Monday, the snow total for the season increased to 105 inches. At about 6,900 feet above sea level, Monday's total reached 61% of its historical average, a figure below normal but expected to increase in the coming days.
“There's still a chance of rain for the first few weeks of February,” Schwartz said.
California water officials will be at Phillips Station near the Sierra at Tahoe ski area Tuesday to conduct their second monthly manual snow measurement of the season. This is largely a ceremonial event in an era when snow gauges throughout the Sierra provide digital readings daily.
Significant storms are forecast to hit Northern California and the Sierra Nevada Tuesday night into Friday, with another round of storms possible Sunday and next Monday.
“This is going to be one of the strongest storms we've seen so far this year,” said Katrina Hand, a meteorologist with the National Weather Service in Sacramento. “This week we've seen water build up on roads and some streams rising near flood stage. And that will bring even more snow to the Sierra Nevada.”
The storm, in the atmosphere from Hawaii, is expected to score a 2 on a scale of 1 to 5 (5 being the strongest) and is expected to dump 1 to 3 inches of rain across much of the Bay Area by Friday. Masu. About 3 to 5 inches are expected in the North Bay and up to 4 to 6 inches in the Santa Cruz Mountains and Big Sur.
The windiest day will be Wednesday, when chain restrictions are expected across the Sierra Nevada, where gusts are expected to reach more than 50 mph.
By Friday, the storm is expected to dump up to 2 feet of fresh snow around Lake Tahoe, up to 3 feet south of Sonora Pass and up to 5 feet on Lassen Mountain.
California often experiences large fluctuations in the amount of rain and snow it receives each year.
“Every winter, water managers bite their nails and invest in Pepcid,” said Felicia Marcus, a visiting scholar at Stanford University's Water in the West Program. “I started this winter feeling anemic, but I'm feeling pretty good now.”
As the planet warms due to climate change, scientists say California is experiencing 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 heavy rain years such as 2017 and 2023.
A series of giant atmospheric river storms hit California last year, ending the state's severe 2020-2022 drought. On February 1st of last year, the snowfall in the Sierra was an astonishing 212% of normal. By April 1, snowfall was the highest in 40 years, 232% of the historical average. Some ski resorts remained open until Independence Day last year.
The fact that this year has started more modestly is in many ways a good thing, experts said Monday.
Last year's heavy rains caused reservoirs around the state to fill up, with water levels still above average for this time of year in many areas. If this winter had started with a new series of atmospheric river storms, the storms could have pushed to the top of the rivers and caused flooding downstream.
“You don't want to fill it up at this time of the season, because if a storm arrives earlier than expected, you risk flooding,” Marcus says. “Droughts are bad, but floods kill people.”
Reservoir managers across the state release more water from reservoirs at the beginning of the winter, from November to February, based on historical records of daily winter precipitation chances, typically when winter winds are strong. It begins to take in more water in March when it blows. Melting snow flows from rivers, allowing more water to flow into reservoirs.
Despite that conservative approach, some of California's largest reservoirs saw impressive increases last month as January storms hit the state.
Water levels at Lake Shasta, the state's largest reservoir at 55 miles near Redding, have risen 20 feet since Jan. 1. Lake Shasta, an important water source for farms and cities, was 79% full on Monday, compared to 112% of normal. For this day.
Similarly, Oroville, the state's second-largest reservoir in Butte County, has risen 23 feet since Jan. 1 and was 76% full Monday, or 132% of its normal level for the day.
Riverside County's Diamond Valley Lake, one of Southern California's most important reservoirs, was 93% full Monday, a big change from a year ago when it was 61% full.
Experts said Monday that unless the rain and snow stop completely starting in mid-February, California should be in decent shape from a water supply standpoint this summer, with no chance of water restrictions in urban areas. He said it was low.
“I think we’ll probably be OK this year,” Marcus said. “But we never want to waste water, because next year could be the start of a 10-year drought.”
