CHALLIS —The varied January weather across Idaho is reflected in the state’s snowpack, the monthly water supply outlook report from the Natural Resources Conservation Service shows.
Data gathered Feb. 5 showed snowpack across Idaho ranging from 83 to 110 percent of median.
That’s not necessarily bad news, according to the report’s author. Water Supply Specialist Ron Abramovich said the second half of winter is yet to come.
“There’s still a chance for the snow to recover to near normal levels by April 1,” Abramovich said, “but we’ll need above-average precipitation in the next few months.” Abramovich pointed out that the January data doesn’t include the heavy snow that has hit much of Idaho in February. Those totals will be in the February report released after March 1. The Feb. 2-5 storm, and several others since then, have added to the mountain snowpack for nearly all of Idaho south of the Clearwater River basin, he said.
The water supply outlook for the Salmon River basin shows January precipitation was 80 percent of average, with the basin at 79 percent of average for the water year, which is technically nine months, running from Oct. 1 through June 30. Sub-basin precipitation levels vary from 74 percent in the Salmon River above Salmon to 84 percent in the Little Salmon. Overall, the snowpack in the Salmon basin was 79 percent of normal. The Little Salmon basin was at 98 percent, while the Middle Fork and Salmon River above Salmon were both at 71 percent.
Runoff forecasts on Feb. 1 for the Salmon basin ranged from 70 to 80 percent.
Near-normal January precipitation was recorded in the Wood and Lost river basins. The Pioneer Mountains received the most monthly precipitation relative to normal, Abramovich’s report shows. Year-to-date those basins are much below average, at around 70 percent of normal precipitation.
The highest accumulation of precipitation last month, relative to normal, was in the Little Wood basin, which received 121 percent of its average January precipitation. On the other end of the scale was the Clearwater basin, which received 57 percent of its average precipitation. Near-normal levels were recorded in the Big Lost, Big Wood, Payette, Weiser, eastern Idaho and Bear River areas. January precipitation was 70 to 90 percent of average in the Salmon, Boise, Mud Lake, Henrys Fork, Upper Snake, Salmon Falls, Bruneau and Owyhee basins. The Panhandle region, Little Lost, Spokane and Oakley basins were also low, at 60 to 70 percent of average January totals.
Snowpack levels in northern Idaho are below average, the report states, at 83 percent. The basins in Weiser, Bruneau and eastern Idaho are at 108 percent of normal.
Streamflow forecasts as of Feb. 1 project runoff volumes ranging from a low of 50 percent of average in the Big Wood basin to 95 percent in the Clearwater basin.
Most of the reservoir systems in Idaho are reporting near average or higher storage levels as of Jan. 31, Abramovich’s report states. Mackay Reservoir was at 70 percent of capacity, which is 119 percent of average. Little Wood was 70 percent full, which is 129 percent of average. And, Magic Reservoir was 44 percent full, which is 122 percent of average.
The report contains a surface water supply index, a predictive indicator of surface water availability within watersheds for spring and summer use. A value of zero indicates a median water supply compared to historical occurrences. The Salmon and Little Lost basins each stand at minus 1.9. The Big Lost and Little Wood are at minus 0.4. The Big Wood above Hailey is at minus 1.3, the Big Wood is at minus 1.5.