Western US snowpack collapses

Snowpack is the West’s mountain water bank, and on April 1 that bank was close to empty across large parts of the region. (drought.gov) April 1 is the benchmark because mountain snow usually peaks around then and melts into rivers through spring and summer. On April 1, 2026, 64% of 1,570 federal snow monitoring sites across the West tied or set record-low snow water equivalent, the water stored inside the snow. (drought.gov) State reports show how broad the collapse is. Washington’s statewide snow water equivalent was 52% of normal on April 1, with 14 stations at record lows, while Utah said April 1 snow water equivalent was the lowest in its recorded history. (nrcs.usda.gov 1) (nrcs.usda.gov 2) Oregon’s April 1 snowpack fell to 15% of the 1991-2020 median, breaking the previous statewide low of 16% set in 2015. Idaho’s peak snowpack reached 68% of normal on March 17, then melted so fast that about one-quarter of it was gone by April 1. (capitalpress.com) (cdapress.com) Colorado’s snowpack dropped into record territory before runoff season after an early, rapid melt in March. The Colorado Sun reported on April 3 that the state was at historic lows, and a March 31 report said Colorado was running about 20% below the previous low for that point in the season. (coloradosun.com 1) (coloradosun.com 2) The Eastern Sierra followed the same pattern after looking healthy in winter. Los Angeles Department of Water and Power said on April 14 that its final survey found Eastern Sierra snowpack at 24% of normal, down from 100% of normal to date on February 10 and March 6. (sierrawave.net 1) (sierrawave.net 2) (sierrawave.net 3) Water managers use snow surveys because snowmelt feeds reservoirs, canals and rivers months after storms end. Washington’s Natural Resources Conservation Service said the April 1 deficit is already pulling runoff forecasts below normal in most basins, and Los Angeles Department of Water and Power said the Eastern Sierra runoff year is now expected to supply close to 40% of the city’s annual demand, or about 81 billion gallons. (nrcs.usda.gov) (sierrawave.net) The runoff problem is not only that there is less snow. A University of Washington study released April 14 found that warmer, drier springs explain nearly 70% of the gap between snowpack-based forecasts and the water that actually reaches the Colorado River. (sciencedaily.com) The mechanism is simple: less spring rain means fewer clouds, more sun, faster plant growth and more evaporation from soil. The study says plants are using more of the snowmelt before it can drain into streams, a shift researchers tie to the Millennium drought that began around 2000. (sciencedaily.com) Agencies are already shifting from measurement to triage. Idaho’s governor declared a statewide drought emergency on April 13, and Los Angeles Department of Water and Power said it is leaning on recycling, groundwater replenishment and other supplies as mountain runoff shrinks. (idwr.idaho.gov) (sierrawave.net) The key date now is not another survey but the runoff season already starting early. Federal drought officials said relief will depend on late-spring storms and the summer monsoon, after the West entered April with record-low snow at most of the places that usually store its water. (drought.gov)