Multiple weak layers are buried in our snowpack right now. Human triggered avalanches remain possible and the avalanche danger is MODERATE above 5000 feet. Avoid areas with a shallow snowpack such as steep, rocky terrain where you can more easily trigger an avalanche. Be aware of wind loaded slopes where cohesive wind slabs may have been deposited on persistent weak layers, especially above treeline. Choose safer terrain if you are uncertain about the stability of the snow.
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Above 6500 ft.
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5000-6500 ft.
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3500-5000 ft.
The relatively warm temperatures over the past week have just begun to strengthen our snowpack. Unfortunately there are multiple buried weak layers located at various depths in our snowpack and they need more than just a few days to heal. It is possible for one or more of these layers to fail given the added weight of a sled or skier. Avoid steep, rocky terrain that often harbors a shallower snowpack. Here you are more likely to trigger one of these persistent weak layers. We have observed very few persistent slab avalanches this season, but do not become complacent about this hazard. Take a little extra time to dig into the snowpack and look for layers of weak snow in areas where you are recreating.
Monday: Erich and Guy rode into China Basin and Werner Peak in the Whitefish Range. They found several weak layers near the surface that are not yet reactive that include surface hoar, the Jan. 19 melt-freeze crust, and a thin layer of facets about 16 inches from the surface as well. Weak, sugary snow also exists near the ground but fractures did not propagate across the column on any layer in stability tests. Skiers in Paola/Dickey Creek in the Flathead Range found about 6 inches of new snow above the Jan. 19 crust, and also found several weaknesses within the top 2 feet of the snowpack, but observed no fracture propagation in their stability tests. BNSF Avalanche Safety toured in John F. Stevens Canyon. They found multiple weak layers in their snow pits, however fractures did not propagate across the column on any layer in stability tests
Sunday: Zachtern was east of WMR in the Whitefish Range where he found buried surface hoar 6 inches below the surface. This layer was reactive in his stability tests but did not propagate.
Saturday: FAC staff were at WMR, in the Whitefish Range, teaching an avalanche class where they noted new surface hoar growth on all aspects at upper elevations. We also noted an overall weak snowpack structure. Skiers east of the ski area boundary noted a 3 cm thick rain crust.
See below for all observations this season.
Our area enjoyed another mild day yesterday with light winds and periods of sun. As of 6:00 a.m. temperatures above 6000 feet range from 8 to 19 ºF. Winds have mostly been blowing from the northeast over the past 24 hours, but have recently begun to shift to the west. Wind speeds have been light, ranging from 2-7 mph with gusts from 11-18 mph. Scattered snow showers yesterday left us about 1 inch of new snow at some locations. For today, expect partly cloudy skies, continued light winds, and no new snow. High temperatures should range from 18 to 27 ºF.
| 0600 temperature: | 8 to 19 deg. F. |
| Max. temperature in the last 24 hours: | 17 to 29 deg. F. |
| Average wind direction during the last 24 hours: | northeast |
| Average wind speed during the last 24 hours: | 2-7 mph |
| Maximum wind gust in the last 24 hours: | 11-18 mph |
| New snowfall in the last 24 hours: | 0-1 inches |
| Total snow depth: | 53-69 inches |
| Tuesday | Tuesday Night | Wednesday | |
|---|---|---|---|
| Cloud Cover: | Partly cloudy | Mostly cloudy, chance of snow showers. | Lingering snow showers |
| Temperatures: | 20 to 27 deg. F. | 6 to 15 deg. F. | 20 to 27 deg. F. |
| Wind Direction: | south to southwest | southwest to west | southwest to west |
| Wind Speed: | 3-4 mph | 3-4 mph | 5-7 with gusts to 17 mph |
| Snowfall: | 0 in. | 0-1 in. | 0-1 in. |
| Snow Line: |
This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires at midnight on the posted day unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.
