Though the avalanche danger is trending downward, you can still get into trouble today. A few more inches of snow can mask the obvious hazard of recently drifted slabs. Start small and use safe test slopes before venturing onto steep, open terrain. Shooting cracks are signs you should step back and make simpler terrain choices. New snow will sluff on very steep slopes. If you want to avoid any problems, seek low angled, sheltered terrain.
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Above 6500 ft.
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5000-6500 ft.
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3500-5000 ft.
Soft slabs broke at middle and upper elevations yesterday. One was triggered by skiers and the other failed naturally from cornice fall. Both involved wind-drifted snow. The storm snow is settling today and slabs may be more stubborn. New snow may cover recent drifts and make them harder to identify. You still can expect to find trouble where recent winds have thickened new snow into slabs. Be extra cautious on steep and leeward slopes below cornices. Use small test slopes to assess the problem before committing to more consequential terrain. Shooting cracks in wind thickened slabs are the surest sign of danger. New unconsolidated snow can sluff in very steep terrain and the consequences can be magnified by terrain traps below. The safest terrain is sheltered from the wind with slope angles less than 40 degrees.
Deep slab activity has waned since a flurry of natural releases in early February. Although slides breaking on weak layers near the ground have become increasingly difficult to trigger, the consequences are unsurvivable. The pattern of deep slabs avalanches this winter has been confined to high alpine bowls and faces in the Flathead Range and Glacier Park on northerly and easterly aspects. Cornice falls are the most likely triggers. Choose routes that reduce your exposure to overhead hazards, including runout zones, and be cautious of alpine slopes with thin or variable snow coverage.
There is an old saying: “The more that changes, the more that stays the same...”
Yesterday, a few storm slab avalanches ran on steep leeward slopes in the Flathead Range. One was triggered by skiers on the sidewall of a gully. A larger slide ran naturally as a result of cornice fall or sluffing from above. Both slides involved wind drifted snow. Observers also reported small sluffs running on very steep slopes. There were some intense convective snow showers with graupel pounding down from the sky in the Flathead, and light showers in the Whitefish Range. Moderate winds loaded leeward slopes with fresh drifts and fragile cornices.
Today, the weather forecast is calling for a few inches of new snowfall for the Flathead and Swan Ranges. New snow should arrive during brief convective bursts in the morning and late afternoon, and may come as graupel. The Whitefish Range will see much less snow with a light shower or two. Light new snow can sluff in steep terrain. Sound familiar?
The primary difference today is the lack of wind. The atmosphere will be calmer today. There may even be periods of blue sky. So while the avalanche problems remain the same, there are a few critical differences today. The storm snow from the past two days is settling. Small instabilities involving fresh slabs of recent or drifted snow will be fewer and further between. Older, harder slabs, the result of previous winds, will be stubborn yet can be large and break in unexpected ways. The danger is on a downward trend, but you can still get into trouble if you step out too quickly without assessing for lingering instabilities first. Use small test slopes before committing to bigger terrain. Use safe travel practices and ride one at a time. If you’re not comfortable evaluating and managing the problems, then seek out wind-sheltered slopes less than about 40 degrees with no terrain traps below.
The National Weather Service has issued a Winter Weather Advisory for our area through 11am due to brief bursts of heavy snow. Otherwise the day should be calm until late afternoon. Temperatures should be a few degrees cooler today and winds much lighter after the most recent cold front passed us by last night. Cold air slips down the east side of the Divide tomorrow bringing a few more snow showers. High pressure builds overhead by mid week.
| Monday | Monday Night | Tuesday | |
|---|---|---|---|
| Cloud Cover: | Mostly Cloudy | Partly Cloudy | Partly Cloudy |
| Temperatures: | 19 to 26 deg. F. | 5 to 9 deg. F. | 17 to 24 deg. F. |
| Wind Direction: | West | West | West |
| Wind Speed: | 10 | 9 | 9 |
| Snowfall: | 1" to 2" in. | 1" to 2" in. | 1" to 2" in. |
| Snow Line: | 1000' | 500' | 0' |
This forecast applies only to backcountry areas outside established ski area boundaries. The forecast describes general avalanche conditions and local variations always occur. This forecast expires at midnight on the posted day unless otherwise noted. The information in this forecast is provided by the USDA Forest Service who is solely responsible for its content.
