California’s snowpack is now the deepest in decades

Drought-weary California enters February with deeper snowpack than in four decades, reflecting a healthy increase in the state’s water supply but also raising concerns about drought in the coming months.

Statewide Sierra snowpack was 205% of normal on Wednesday, Department of Water Resources officials said during the second snow survey of the season.

Even more encouragingly, snowpack was 128% of its April 1 average, referring to the end of the season when snowpack is typically at its deepest in California.

“Our snowpack has gotten off to an incredible start, and that’s exactly what California needs to really help overcome our ongoing drought,” said DWR Snow Surveyor Sean de Guzman. The state’s snow cover is currently surpassing the winter of 1982-83 — “the wettest year on record for about 40 years,” he said

Snow levels at Phillips Station near South Lake Tahoe, where monthly surveys are conducted each winter, were 193% of the average for the date.

California’s snow is an important part of the state’s water system, providing about one-third of its supply. Snow is especially important during the hot, dry summer months when it slowly releases more water as it melts.

This year’s bounty is a direct result of the atmospheric river storms that battered California in late December and into January, De Guzman said. The storms dumped trillions of gallons of moisture across the state, filling up reservoirs and burying mountainous areas under several feet of powder.

It was enough for DWR to tentatively increase its allocation of reserves to the state’s water authorities from 5% to 30%. However, officials on Wednesday expressed concern about the state’s recent return to drought.

“We really don’t know here on February 1 if this is the peak of our snowpack,” said DWR Director Karla Nemeth. She added that it’s “too early to say” if the wet January will be enough to break the state’s drought.

“While today’s results are good news for water supplies, we know from experience how quickly snow cover can disappear when dry conditions return in the coming months,” she said.

There’s no denying that January started off strong. On Monday, the UC Berkeley Central Sierra Snow Lab at Donner Pass reported that it had achieved a season total of 360 inches — a number that is typically an average over a full year.

“When we get to that average, it’s generally much later in the year,” said lead scientist Andrew Schwartz. “We’re getting there effectively three months ahead of schedule, which is absolutely fantastic. We are definitely in an excellent position for the future.”

While heavier snow has been seen in previous years — meaning more water in the snow pack — Schwartz said Wednesday that the amount of snowfall was the highest the lab had seen since its digitized records began in 1971.

Under normal conditions there aren’t many downsides to such a strong start to the season, he said – with a few exceptions.

“If we go outside of normal conditions and experience something like another rain-on-snow event, which is very warm, it could cause quite significant and catastrophic flooding,” he said. “Because rain likes to melt the snow.”

Another concern is that all of California’s rainfall can lead to additional grass growth, especially at lower elevations, which can lead to wildfires in the summer, Schwartz said.

But he added: “I think the benefit of having that much snow cover far outweighs any of those risks.”

There were other benefits too. The storms, which followed the state’s driest three years on record, pulled all of California out of the two worst drought categories — extreme and exceptional drought — according to the US Drought Monitor. Just three months ago, 43% of the state fell under this classification.

Reservoirs also experienced a boost. Lake Shasta ended January at 56% capacity, up from 33% a month earlier. Lake Oroville was at 65% occupancy, up from 36% at the end of December, according to state data.

However, Nemeth said there are also some concerns about evaporation as the state’s atmosphere becomes warmer and drier due to climate change.

In 2021, the state reported a sharp decrease in snow runoff, largely due to warm temperatures and snow penetrating dry soils, she said.

“Warming temperatures represent an increased demand for our available surface water, and these are the things we monitor very closely that can affect our runoff into rivers, streams and reservoirs,” she said.

That hasn’t stopped many Californians from enjoying the powder. At Sugar Bowl Resort near Lake Tahoe, spokesman Jon Slaughter said Wednesday the snow was so deep he couldn’t see out his second-story window.

“It’s going to be a great year,” said Slaughter. “We’ve seen great snowfall and we have another foot on the rise this weekend.”