Idaho faces a potential water shortage as an unusually warm winter leaves mountain snowpack well below normal, raising concerns about summer water supply.
BOISE, Idaho — Water managers across Idaho are watching mountain snowpack closely after an unusually warm winter left snow levels well below normal in parts of the state, raising concerns about water supply and wildfire risk later this summer.
Snowpack in the Boise River Basin, which supplies water to the Treasure Valley, is currently about 70% of normal, according to the U.S. Department of Agriculture’s Natural Resources Conservation Service. Manual snow course measurements suggest the figure could be closer to 60% of normal.
“We haven’t really seen dry conditions like this since 1977,” said Erin Whorton, a water supply specialist with the Natural Resources Conservation Service.
Snowpack acts as a natural reservoir in Idaho’s mountains, slowly releasing water into rivers through the spring and summer. But this winter, much of the precipitation that normally falls as snow instead came as rain, sending water into rivers and reservoirs earlier than usual.
Despite the low snowpack, reservoirs in the Boise River system, including Lucky Peak, Arrowrock and Anderson Ranch, are currently in relatively strong shape after recent rain boosted storage levels.
Water managers still expect the Boise River reservoir system to fill this year, and flood-control releases from Lucky Peak Reservoir could begin as early as March 26, according to the U.S. Army Corps of Engineers, Walla Walla District.
The larger worry is what happens later in the season.
With less snow stored in the mountains, rivers could lose their natural flow earlier in the summer, causing problems for those who rely on a consistent source of water downstream.
“That forces agricultural producers to rely on storage water, groundwater or other sources of water sooner than they would normally have to,” Whorton said. “That places stress on their operations if they don’t have the water in the spring that they would typically have.”
Statewide snowpack levels vary, but many basins across Idaho are between 60% and 85% of normal, according to state monitoring data.
The warm winter also raises concerns about wildfire conditions later in the year. Drier landscapes and earlier snowmelt can extend the wildfire season and increase the potential for smoke across the region.
“That widens the opportunities for wildfire activity,” Whorton said. “Because the states around us are also dry, there is a greater chance that we might have smoke impacts this year.”
Water managers say conditions could still improve if Idaho sees a cool, wet spring with additional mountain snowfall. However, current forecasts are trending warmer and drier.
“We would love to see temperatures get colder and get a few more snowstorms to bolster the snowpack,” Whorton said. “Frankly, that doesn’t look likely.”
Officials say farmers, water managers and residents should be watching water forecasts closely in the months ahead as Idaho heads into the summer irrigation season.