Uncommon Knowledge
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Extreme snowfall will become less common in California by 2100, a new study found.
Scientists understand how a lack of snow or “snow drought” can affect a region, especially in the midst of a warming climate. However, before now, they did not understand the impact of unusually high levels of snow. And this is becoming more important, as California has just emerged from its second winter of high snowfall.
A new study published in the Proceedings of the National Academy of Sciences used the 2023 winter as a case study to learn more. Computational hydrologist Adrienne Marshall and colleagues from the Colorado School of Mines dubbed the term “snow deluges” to describe the phenomenon recently seen in California.
To reach their findings, they analyzed the unusual snow deluge across the Sierra Nevada mountains in 2023 to assess the impact of “high snow years.”
In 2023, California saw an extremely high amount of snow accumulation, with record snowpack levels. Observations showed the accumulations were a “once-in-54-years event,” with some areas reporting “once-in-320-years accumulations,” the study reported.
By looking at climate projections, scientists found that years like these with the so-called “snow deluges” are set to decline by 58 percent by the end of this century. Years with median levels of snowfall are also estimated to decline by 73 percent, they reported.
“California’s massive snow year of 2023 was record-breaking at 42 percent of snow monitoring sites,” Marshall told Newsweek. “Climate models indicate that in warmer future climates, our biggest snow years will be smaller than our biggest snow years now. Another way of putting this is that a snow deluge like we saw in 2023 would be much more rare in a warmer climate like that we might expect later in the 21st century.”
Similar patterns will also be seen across the wider Western U.S., the study reports.
The findings “underscore the significance of uncovering the impact of climate change on the dynamics of snow deluges and snow droughts in mountainous regions,” the study reports.
“These findings align with a bigger scientific picture that shows declining average snowpack and more frequent snow droughts in California and throughout the West,” Marshall said. “Our new findings suggest that we shouldn’t count on big snow years like the one we had last year to save us in warmer climates.
“This is important because snow acts as a natural reservoir in the mountains that stores water until the late spring and summer when we need it most. Our best opportunities to avoid the worst consequences of this snow loss lie in reducing our greenhouse gas emissions and finding ways to adapt to adapt to changing snow and water availability.”
The study notes that snow deluges can be “both destructive and beneficial” meaning better understanding of the phenomenon can improve management of “snow-dependent ecosystems and economies.”
The 2023 snow deluge in California, in many ways, could be seen as good thing. Before it occurred, the state had been suffering from prolonged drought conditions. As a result, there was a severe lack of snowpack in the surrounding mountains, meaning less water was feeding the state’s reservoirs.
The large snow build-up, however, meant that come spring, it melted into rivers and reservoirs, saving the state from a water crisis. In fact, drought conditions in the state officially ended.
However, the heavy snowfall indicates that climate change is worsening, as weather patterns become more unpredictable and extreme. While the drought has ended for now, climate change could cause another prolonged dry period in the future.
“Snow is important for both ecosystems and water resources, and there’s a lot still to learn about how our biggest snow years—or the loss of them—impact these systems,” Marshall said. “The present study focuses on annual-scale snow deluges, but the largest individual snowfall events could change in different ways.
“We focused on a moderate warming scenario in California and the Western U.S., but it would also be helpful to learn more about how different climate scenarios could affect snow deluges in other parts of the world.”
Do you have a tip on a science story that Newsweek should be covering? Do you have a question about California snowfall? Let us know via science@newsweek.com.
Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
An annual pass that’s usually $50 is free in honor of Juneteenth — and to mark the 250th anniversary of the signing of the Declaration of Independence.
Historical buildings are visible at Sonoma State Historic Park, Sonoma, California, May 31, 2026. Until July 6, Californians can download the state historic park pass for free and use it as many times as they want through the end of 2026. (Smith Collection/Gado via Getty Images)
“California doesn’t hide from hard truths and uncomfortable history – in fact, we embrace it and learn from it,” Newsom wrote.
Until July 6, Californians can download the state historic park pass for free and use it as many times as they want through the end of 2026. The pass gives free entry to state historic parks for up to four people.
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The Historian Passport grants entry to more than 30 state historic parks, including parks like Olompali and Malakoff Diggins which, rather than just providing outdoor recreation, also have an educational emphasis on the state’s history.
Many of these parks tell the story of the state’s cultural or indigenous history, from missions and museums to temples and the site that sparked the California Gold Rush.
Newsom made a similar move to make state parks free for Martin Luther King Jr. Day this year, in response to Trump’s decision to eliminate the holiday from the list of fee-free days at national parks across the country, replacing it with his birthday on Flag Day.
You must make an account with the state’s reservation site ReserveCalifornia.com to obtain a Historian Pass. Then, visit the site’s Advance Passes page and select “Special Edition Historian Passport” from the dropdown menu, which will show as costing $0. No payment information is required.
After checking out, you’ll receive an email with an attached PDF version of your Historian Passport.
The state recommends you print off this PDF to present at any California state historic park for free entry, although you may just be able to show the image on your phone too.
Bear in mind that cellphone service may be poor at many state historic parks, so it’s worth screenshotting the PDF to save it as an image on your phone in case you’re unable to search your email.
Looking for free entry to other state parks that aren’t included in the Historian Passport? Consider checking out a parks pass from your local library, which provides these passes as part of the California State Library Parks Pass program.
Bay Area
Sacramento area
Sierra foothills
KQED’s Carly Severn contributed to this report.
A 33-year-old Northern California man was sentenced to three years in prison after he was found passed out drunk behind the wheel in the drive-thru of an In-N-Out Burger, marking his seventh arrest and conviction for driving under the influence.
According to the Monterey County District Attorney’s Office, California Highway Patrol officers were alerted to the June 2025 situation by a store employee.
Responding officers approached the vehicle and reported smelling urine and vomit, along with the odor of alcohol inside the car, the Los Angeles Times reported.
Officers arrested the man, identified as Carlos Alvarez of Salinas, on suspicion of felony DUI.
This was his fourth DUI conviction in the past 10 years, The Times reported.
It was not immediately clear what sentences were imposed in Alvarez’s prior DUI convictions or whether he has previously served jail time for any of the other felony convictions.
Two college students died after being swept out to sea from a Santa Cruz beach as massive waves and dangerous rip currents inundated the California coastline in recent days.
Authorities confirmed this week that Harshita Nair, 21, and Mahial Sran, 20, were killed after the sudden swell at a Santa Cruz beach last Wednesday. Nair died last week while Sran died in a local hospital on Sunday.
The incident came a day after a five-year-old girl in southern California was killed when turbulent waters swept the child, who was walking with her mother and brother, out to sea from the shore of Treasure Island Beach in Orange county.
Authorities have urged people to take precautions while visiting beaches throughout the state as the coast faced treacherous conditions with the continuing king tides, a non-scientific term describing the highest tides of the year.
On 10 June, local authorities in Santa Cruz responded to a beach for an ocean rescue of two women who had been pulled into the water. A team of about eight rescue swimmers helped pull Nair and Sran from the water, and they were taken to local hospitals by ambulance and helicopters.
It was the fifth rescue firefighters had undertaken on that mile-long portion of coastline from Yellow Bank Beach to Bonny Doon Beach, the San Mateo-Santa Cruz unit of Cal Fire said in a statement online.
Kyle Breton, a Santa Cruz county volunteer fire captain, said in a video that officials believed the two friends were napping near a rock archway between two beaches when the water came in and swept them out.
Sran was a student at San Jose State University and Nair attended the University of California, Berkeley, the universities confirmed to media outlets.
In an obituary, Nair’s family remembered her as a “cherished sister, granddaughter and a treasured friend” who “always found a way to lift others up”.
“Harshita was truly full of life – radiating energy, warmth and joy wherever she went. She had a deep love for adventure and embraced every moment with enthusiasm and courage. Her spirit was contagious, her laughter uplifting and her presence comforting.”
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