As of Tuesday, April 17, 2018
The stage is set: Early April is when Idaho’s mountain snowpack generally reaches its peak snow water content, “… and things are looking interesting for the water supply picture,” said Ron Abramovich, Water Supply Specialist for the Idaho Natural Resources Conservation Service (NRCS).
According to the April water supply outlook report, precipitation since the water year started on Oct. 1, 2017, varies across the state with watersheds ranging from 85 to 120 percent of normal.
Current snowpacks range from half of normal in the Owyhee basin to 120 percent of normal in the Clearwater and Upper Snake. These amounts are much less than last year, except in the Clearwater and north, where there is more snow than a year ago.
“We may not have seen the peak snow water content amounts yet, as additional storms are predicted to move into Idaho in April,” Abramovich said.
According to the report, March precipitation was below normal for only the second month this water year with amounts ranging from 75 to 90 percent across the Clearwater basins. Precipitation since the water year started for the basin as a whole is 120 percent of normal, highest in the state, and 83 percent of the annual precipitation total with five more months still to go.
Snowpacks range from 118 percent of normal in the North Fork Clearwater basin to 134 percent in the Selway basin, one of the highest in the Idaho NRCS monitoring region. This year’s snowpack is the highest since 2014 and more similar to 2012.
Abundant moisture is forecast for northern Idaho in early April that will melt the remaining low elevation snow and start melting the mid-elevation snow at sites such as Crooked Fork, 3,610 feet.
Streamflow forecasts remain consistent across the basins, including 127 percent of average for the Selway River.