Idaho’s snowpack is well above normal throughout the state, but it’s still early in the season

“The memory of little to no snowfall for three months last winter still stings, and despite the healthy snowpack, reservoir storage is very low throughout much of the state” hydrologists with the Natural Resources Conservation Service in Boise said in their January water supply outlook report.

As of Jan. 9, the Upper Snake River system is at 34% of capacity, and the Boise River system is at 53%, according to the Bureau of Reclamation.

“In order to fully recover from drought, we need an ample snowpack to replenish depleted reservoirs and provide sufficient springtime natural streamflow before irrigation deliveries begin,” the hydrologists said.

While more than 70% of Idaho’s surface water supply comes from mountain snowpack, spring precipitation, the timing of snowmelt, soil moisture and shallow groundwater conditions also play a major role in water supply resiliency.

The first part of January is expected to be wetter than normal across all of Idaho. The one month outlook from the National Oceanic and Atmospheric Administration (NOAA) suggests increased chances of above normal precipitation in central and southern Idaho.

Warmer than normal temperature conditions are predicted near the Canadian border with wetter-than-normal conditions in southern Idaho.

Currently, 72% of Idaho lands are in moderate to severe drought compared with normal, and the remainder of the state is abnormally dry. The seasonal drought outlook forecasts widespread drought improvement across Idaho.

According to the NOAA drought-reduction tool, Idaho needs about 120% of normal precipitation to fully end hydrological drought by June in the Upper Snake Basin and about 160% of normal precipitation in the Wood River basins.

“The probability of ending drought conditions is much higher compared to last year, and the chances of drought conditions significantly improving by June across the entire state are very favorable at report time,” the hydrologists said.

For now, the snowpack is in good shape as all basins across the state are above normal and range from 121% to 172% of normal. Idaho’s fourth coldest November on record preserved early-season snowfall throughout much of the state.

“Although this wasn’t good for snowpack stability in terms of avalanche hazards or potentially locking in dry soil conditions that could affect spring runoff efficiency, the cold temperatures through November and December gave us an early start to building the snowpack we need this water year,” the hydrologists said.

Idaho needs an above-normal snowpack this winter to fill reservoirs and rejuvenate natural flow conditions come spring.

“We are on track to meet water supply needs this irrigation season at this point in the winter due (to) above-normal snowpack conditions. However, there is still a lot of winter ahead of us,” the hydrologists said.