Idaho's Historic Snow Shortfall

Idaho is heading into spring and summer with one of its worst snow years on record, and federal forecasters say water shortages are likely across much of the state. (nrcs.usda.gov) Snowpack is Idaho’s mountain water savings account: the snow builds through winter, then melts into rivers, reservoirs, farms, and city systems. The Natural Resources Conservation Service said Idaho’s snowpack peaked on March 17 at 68% of normal, nearly three weeks early. (content.govdelivery.com) By April 1, about 25% of that statewide snowpack had already melted away, even at high elevations, after a warm winter and a mid-March heat wave. The National Integrated Drought Information System said Idaho set a new record-low April 1 snow-water-equivalent value in the SNOTEL era that began in the 1980s. (bonnersferryherald.com; drought.gov) The shortfall is not just a ski-season problem. The Natural Resources Conservation Service said spring and summer streamflow volumes are likely to approach or fall below historical minimums across many western basins, with southern Idaho among the hardest-hit areas. (nrcs.usda.gov) That reaches far beyond irrigators. Idaho’s snow survey program says its runoff forecasts guide decisions on agricultural production, municipal and industrial water supply, fish and wildlife management, hydropower, flood control, and water quality. (nrcs.usda.gov) State officials have already moved on the drought. On April 13, the Idaho Department of Water Resources declared a drought emergency for all 44 counties, citing Natural Resources Conservation Service forecasts that put 19 basins in some level of drought and four at or below the 2nd percentile. (idwr.idaho.gov) The order also laid out where shortages could bite first under normal spring weather. It said there is a 50% chance of irrigation shortages on the Boise and Snake rivers, and estimated water supplies short by 44% in the Oakley basin, 53% in the Big Wood basin, and 58% in the Salmon Falls Creek basin. (idwr.idaho.gov) Some reservoirs are in better shape than the snowpack, which could soften the blow in a few places. Industry and state reporting on the April outlook said Southern Snake reservoirs ranged from 101% of normal at Owyhee to 55% at Salmon Falls, even as runoff forecasts stayed well below average. (capitalpress.com) Late April storms have added fresh snow in parts of Idaho’s high country, but they have not erased the weak base. OpenSnow’s statewide report on April 20 still showed many Idaho areas far below average seasonal base depth, including Magic Mountain at 1% of average, Pebble Creek at 11%, and Pomerelle at 26%. (opensnow.com) Federal forecasters now say the next few months will decide how severe the damage becomes. Drought.gov’s April 9 update said the April-to-June outlook favors continued warmth across the West, leaving any real relief to late spring storms and summer monsoon moisture. (drought.gov)