Out of all 12 western U.S. states, Montana was the only one with normal or better snowpack conditions in all basins within its borders as of Feb. 1, according to the USDA Natural Resources Conservation Service.
“La Nina weather patterns this year have favored the northern tier states across the western U.S. and so far Montana and Wyoming have been the big winners,” said Lucas Zukiewicz, NRCS water supply specialist for Montana.”
Building on a strong early season snowpack, January provided consistent moisture to the basins in the state, although the approaching storms from the West Coast came in with above-normal temperatures. Many mountain locations were 3 to 7 degrees above average, which resulted in a mix of snow and rain through the month west of the Continental Divide. Mid-month the rain levels reached mid to high elevations, raining over an inch on the mountain snowpack in some locations.
“Even with the warmer-than-average weather, the mountain snowpack stood strong through the month with little to no discharge at water yielding elevations,” Zukiewicz said. “The water was stored in the snowpack until runoff in the spring, thanks to a cold snowpack in place from the month of December.”
The snowfall starting Oct. 1 hasn’t been record-breaking in most locations, but has been above normal, according to NRCS data. However, Zukiewicz pointed out there are some records in central and southwest Montana. The Frohner Meadow SNOTEL site south of Helena and eight other SNOTEL sites and snowcourses are recording the second highest snow water equivalent totals for Feb 1.
Percentage-wise, the best snowpack in the state can be found in the Upper Clark Fork at 140 percent, Missouri Mainstem near Helena at 148 percent, Upper Yellowstone with 148 percent and Gallatin River at 129 percent of normal. Statewide, Montana sits at 117 percent of normal precipitation and 124 percent of snow to water equivalent.
The snowpack data is great news for water users in the state, but a healthy dose of caution is still warranted, according to the NRCS.
“Getting complacent, or bragging about snowpack at the beginning of February would be like bragging about leading Daytona halfway through the race,” Zukiewicz said. “It doesn’t matter where you are halfway through it, it matters where you’re at when it wraps up.”
Snowpack typically peaks across the state during April or May, depending location. The coming months are critical for water supply, and in many basins east of the Continental Divide the months of March, April and May typically provide significant precipitation.
“Should La Nina and associated weather patterns continue to favor the state with above-normal snowfall, or even normal snowfall from this point, water supply could be more than adequate for irrigation and recreation this summer,” Zukiewicz said. “But, if the pattern takes a turn, and the snow faucet shuts off, the prospects of our water supply would be diminished.”
With several inches of snow to start the workweek and subzero temperatures along the Hi-Line, Montana is bracing for another winter storm starting Thursday.
With a widespread storm, low temperatures are forecast to drop to single digits starting Thursday night with highs of 15 to 20 degrees Friday and Saturday in Helena, according to the National Weather Service in Great Falls. Forecasters predict 3-6 inches of new snow in the Helena Valley with up to 13 inches on MacDonald Pass.