Flathead snowpack likely to end season at 78% of median

The region’s snow pack will likely end up about 22% less than a normal year. The Flathead River Basin snowpack is about 78% of the median, which is up a few percentage points since a storm dumped more snow in the high country over the weekend.

But typically the snowpack starts losing mass about mid-April onward, particularly at low elevations.

“February did provide well above normal precipitation to nearly all of Montana and those weather patterns continued into the first week of March across the state,” Eric Larson, a U.S. Department of Agriculture Natural Resources Conservation Service Water Supply Specialist said. What seemed to be the beginning of a potential recovery only tapered off in many basins. Overall, precipitation during March was above normal in southwest and southern Montana, but below normal elsewhere.

The lowest snowpack recorded in the Flathead River Basin was 65% in 2005. Other years also saw low snowpacks — 73% in 2015, 74% in 2020 and just 68% in 2001.

Statewide the snowpack is very much a mixed bag.

“The good news is the southern Absaroka and Wind River region has received near normal precipitation this season, as a result the Bighorn River basin snowpack is 95% of normal,” Larson noted. 

In contrast, snowpack percentages are currently about 55-65% of normal in the Sun-Teton-Marias, Smith-Judith-Musselshell, Upper Clark Fork, and Powder River basins. All other river basins in Montana have about a 70-85% of normal snowpack. 

“Keep in mind that the lowest April 1 snowpack percentages since 1991 are about 50-70% of normal. One example is the Gallatin which currently has a 76% of normal snowpack. The lowest April 1 snowpack percentage since 1991 was 73% in 2001, which is not too far off from this year and also 2022,” Larson said.

Snowpacks are critical for river health, as the melting of snow over time keeps the waters cool and sustains flows in warmer months.

In the Flathead Basin, the deficits vary widely. The Noisy Basin Snotel in the Jewel Basin is 94% of average, while Kraft Creek is just 55% of average. Blacktail Mountain is also just 59% of average.

Flattop Mountain in Glacier National Park is 81% of average. That deficit means several feet of snow, however, as the site is almost 9 inches of snow water equivalent below normal.

Snow water equivalent is the amount of liquid water in the snow. If you took a height of snow and melted it, the height of the water created is SWE. For example, if 10 inches of snow falls at 10% density, then there would be 1 inch of SWE.

The weather this weekend is expected to be warm and wet, with highs in the 60s.

This story was edited to clarify that the percentages are of the median, not the average.