Posts

Snow Loss is Fueling the West’s Megadrought

Lake Mead is America’s largest reservoir, supplying water for 25 million people across the southwest. It’s also drying up — a kind of poster child for the ongoing drought in the West. But upstream, a much larger but lesser known source of stored water is also disappearing: mountain snow.

This is how climate change is throwing one of the United States’ most critical sources of water out of whack.

Record Drought Conditions Across West Raise Concerns for Summer Dry Season

The current multi-year drought across the West is the most extensive and intense drought in the 22-year history of the U.S. Drought Monitor. Precipitation deficits during the first three months of 2022, across parts of the western U.S., are at or near record levels. As the climatological wet season ends across portions of the West, with below average snow cover and reservoirs at or near record-low levels, concerns for expanding and intensifying drought and water resource deficits are mounting.

During March, the average contiguous U.S. temperature was 44.1°F, 2.6°F above the 20th-century average. This ranked in the warmest third of the 128-year period of record. The year-to-date (January-March) average contiguous U.S. temperature was 36.3°F, 1.2°F above average, ranking in the middle third of the record.

The March precipitation total for the contiguous U.S. was 2.26 inches, 0.25 inch below average, and ranked in the driest third of the 128-year period of record. The year-to-date precipitation total was 5.66 inches, 1.30 inches below average, ranking seventh driest in the January-March record.

Temperatures were above average across much of the West and along the East Coast. California ranked sixth warmest for the January-March period.

Snow Drought Expands as Western U.S. is Running Out of Time to Replenish Water Supplies

February total precipitation was record low at over 200 Snow Telemetry sites, leading to continued expansion of snow drought conditions across the West. Fifty percent of the SNOTEL sites now have snow water equivalent that is less than one-third of historical conditions, up from 22% in early February.  In California, the driest January and February in state history has led to a March 1 statewide snowpack of less than 70% of average, down from 160% at the start of the new year.

California Snow Drought Ends in Dramatic Fashion, While Other States Still Deal with Shortage

Thanks to multiple atmospheric river events, average snowpack in California has gone from 18% to 98% in just two weeks.
“Increases in snowpack of this size are not common, but also not unprecedented,” Julie Kalansky, deputy director of operations for the Center for Western Weather and Water Extremes (CW3E), explained.
Kalansky pointed out previous studies have shown a jump on this scale can happen about twice every three years, but usually over the course of an entire winter, not just the month of December. While they don’t have the exact rankings for each month of the year, “most of the storm events in the study we referenced for the above calculation were in the second half of December and later into the season,” Kalansky added.
The sudden change gives California its wettest start to the Water Year in more than 40 years, thanks to several drought-denting rain and snow systems pushing through the area in recent weeks. The Water Year runs from October 1 through September 30 of the following year.

‘Snow Drought’ is Threatening the Western US, and That Could Become a Massive Problem

The western United States has built their water infrastructure on a melting foundation, and unless we do something about global warming, scientists worry the consequences will be catastrophic.

‘Snow Droughts’ Are Coming For The American West

On April 1 each year, researchers ski and snowshoe out into the high mountains of the western United States to jab stakes into the bright, crystalline snow, checking the thickness of the blanket. But in 2012, many researchers could barely travel on snow to their test sites—and when they got there, there was almost no snow to measure.

2013 was almost as bad. 2014, the same. And in 2015, on the April 1 assessment, many sites across the Sierra Nevada mountains were bald and snowless—the worst snow drought, scientists found, in at least the last 500 years.