First snow of the season falling at Tahoe, Yosemite

It’s not time to break out the skis just yet. But in a symbolic turning of the page for California’s annual weather story, the first measurable snow of the winter season began to fall Wednesday in the Sierra Nevada.

Flurries were visible by mid-day at Donner Summit along Interstate 80. Forecasters said that 1 to 2 inches were expected overnight around mountain passes, with 2 to 4 inches possible at higher elevations above 8,000 feet, and 6 inches on Mount Lassen in far Northern California.

Most of the snow will melt by Thursday, meteorologists said. And Tahoe area ski resorts aren’t scheduled to open for another month.

But the fact that temperatures were forecast to fall into the 30s, and even 20s at higher elevations, was causing a stir.

“It is an early season system,” said Katrina Hand, a meteorologist with the National Weather Service in Sacramento, of the storm from the Pacific Northwest. “We don’t have cold, cold air yet, so the snow levels are relatively high, but it’s still kind of exciting.”

Oh yeah, that's the good stuff! Glad to see #snow back at the lab! pic.twitter.com/oRv2HoxHwu

— UC Berkeley Central Sierra Snow Lab (@UCB_CSSL) October 25, 2023

Wind gusts were forecast Wednesday night between 75 mph and 85 mph at the highest mountain passes.

Farther south, officials at Yosemite National Park announced that the Tioga Road — the main paved route through the park’s high country, winding from 6,200 feet up to 9,900 feet elevation — would close temporarily at 6 p.m. Wednesday night due to the snow. It was expected to reopen later this week, although the park did not issue a specific time.

The generally light dusting of snow across the Sierra is the first significant snow in nearly 6 months. The last time it snowed at Donner Summit and did not instantly melt was on May 7, when 4 inches fell, said Andrew Schwartz, lead scientist and manager of the UC Berkeley Central Sierra Snow Lab.

“It’s always exciting after going a while without snowfall,” he said. “This past year we definitely had a shorter break than usual. But in typical years the first snowfall indicates the beginning of the end of fire season. And these early snows and rains help bulk up our soil moisture which helps with runoff for water supply later in the year.”

Hydrologists measure the “water year” in California each year from Oct. 1 to Sept. 30. That way, the winter rainy season, which spans the end of one year and the beginning of another, can be measured as one event.

Last year ranked among the biggest snow years in California history. At the UC snow lab near Donner Summit, 754 inches — or 62 feet — fell as more than 30 atmospheric river storms barreled in from the Pacific, filled reservoirs, ended California’s three-year drought, and buried Tahoe-area ski resorts in so much snow that they had to close at times to dig out the ski lifts. That total was the second-highest in the lab’s history, behind the winter of 1951-52, when 812 inches fell.

On May 1, the Sierra Nevada snowpack was 254% of its historical average, according to the state Department of Water Resources. That was the second-highest May 1 reading since 1950 when modern records began, behind only 1983, when it was at 289%.

But fears of a “Big Melt” that would cause huge flooding damage across the foothills and the Central Valley never materialized. The reason: Temperatures were mild in late spring, and the state was not hit with the kind of warm “Pineapple Express” storm from the tropics that could have caused very rapid melting.

There's snow doubt that Lassen National Park is looking at the highest accumulations today, with 6-8 inches predicted to fall before 5 AM Thursday. Most other mountain locations will see 2 inches or less, and most snow likely won't stick around for long.#CAwx pic.twitter.com/nPBYfGnt6b

— NWS Sacramento (@NWSSacramento) October 25, 2023

No one knows how much rain or snow California will receive this winter. With El Niño conditions developing in the Pacific, chances of a wetter-than-average winter are high, according to a seasonal forecast issued last week by the Climate Prediction Center, a federal department that is part of the National Oceanic and Atmospheric Administration.

But those long-range predictions from NOAA have been notoriously wrong. Last winter, for example, the agency predicted a drier-than-normal winter for California, and a deluge occurred.

Nevertheless, public officials around the state have begun to alert the public to be aware of flood risks. On Wednesday, Gov. Gavin Newsom issued a statement saying that the current state budget has $95 million for flood preparedness and recovery projects, much of it to repair and strengthen levees on rivers and creeks across the state. A failed levee on the Pajaro River on the Monterey-Santa Cruz county border caused significant flooding in March.

Wednesday officials in San Jose held a news conference to recommended Bay Area residents living near rivers begin to prepare for winter, noting that the city and the Santa Clara Valley Water District have been clearing storm drains, opening sandbag stations and taking other measures to reduce flood risk before heavy rains begin.

“We all know extreme weather is the new normal,” said Barbara Keegan, vice chairwoman of the Santa Clara Valley Water District. “We all need to be ready for storms and the potential for flooding.”