Just weeks after major storms brought snow to the Sierra Nevada, a winter heat wave has all but eliminated California’s snowpack gains. Satellite photos from NASA reveal the extent of this significant melting event, which took place in late February and early March.
“The extremely rapid loss of the snow that fell during the late February storm cycle, which in many cases dropped multiple feet of snow in the Sierra Nevada over just a couple of days, is genuinely remarkable,” said Daniel Swain, a climate scientist with UC Agriculture and Natural Resources, in an email to The Times.
The images below show the Sierra Nevada from space on February 22 (left) and then on March 3. In less than 10 days, the snowpack receded significantly amid a heat wave that pushed temperatures 15 to 20 degrees above normal across much of California.
As forecasters predict above-average temperatures for the coming weeks, Swain warned that snowpack losses are likely to continue.
California depends on the Sierra snowpack for approximately 30% of its water supply. However, this winter’s extreme warmth across the Western United States has resulted in more precipitation falling as rain rather than snow—a symptom of global warming, experts say. This trend has been pushing average snow lines higher in the mountains and altering the timing of runoff in recent years.
There are 130 monitoring stations across the Sierra Nevada providing electronic readings of the snowpack. Currently, the northern Sierra is at 38% of its average snowpack, while the southern Sierra stands at 83% of average. For comparison, on February 22, the southern Sierra was at 98% of normal.
Another set of images compares the Sierra on February 12 (left) and March 3. Despite heavy snow that blanketed the mountains between those dates, the snow levels had retreated back to early-February conditions by March 3.
Swain noted that although significant moisture remains in California’s mountains, the reduced snowpack is likely to impact the state’s water supply and increase wildfire risk later this summer.
“The very early loss of snowpack will effectively make the long, dry summer that much longer in the mountains,” he said.
https://www.latimes.com/california/story/2026-03-05/satellite-photos-california-snowpack-early-meltdown