The snowpack continues to strengthen following storms early last week. However, thick slabs over buried weak layers remain a low probability/high consequence problem. Terrain selection remains key: steep leeward terrain is most suspect. Carefully evaluate snow and terrain.
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Above 6500 ft.
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5000-6500 ft.
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3500-5000 ft.
Buried weak layers continue to gain strength but remain a concern. In the Flathead Range, Tuesday's storm overloaded these layers which resulted in several large avalanches. Persistent slabs surprise us with their ability to be remotely triggered and produce unusually wide avalanches. Managing this problem is best achieved through terrain selection. Steep leeward slopes are most suspect due to harboring weak layers under a thick hard slab. Sheltered terrain generally offers a safer option.
Benign weather is allowing our snow surface to strengthen and recover from Tuesday's storm. It has been several days since we have received a report of a wind slab or storm slab avalanche. Field observations reveal limited surface instabilities. Thus we have dropped wind slab from today's forecast of avalanche problems.
Unfortunately, buried weak layers continue to lurk beneath the surface of our snowpack. These layers are also gaining strength but at a much slower rate than at the surface. Buried weak layers are notorious for awakening after a period of dormancy. Triggers include riders, snow machines or a new load of snow. Digging into the snowpack and performing stability tests may result in a no-go decision. But, these tests should not offer you the green light. The best solution for dealing with persistent slabs is terrain selection. Persistent slab avalanches earlier last week occurred on steep wind-loaded terrain. There, a thick hard slab rested on top of the weak layers producing unusually wide and surprising avalanches. Gladed slopes sheltered from the wind offer a safer option.
A storm system will move into our area today depositing light to moderate snow at all elevations. Today's snow is not expected to increase the avalanche hazard by nightfall. Expect areas of deeper snow on the leeward sides of ridgelines and in cross-loaded gullies. Small loose dry avalanches along with thin slabs may develop by the end of today.
We are offering an Avalanche Awareness talk Thursday, December 27 at Stumptown Snowboards at 7:00 p.m.! We are offering a Motorized Level 1- Avalanche Fundamentals course January 11-13!
A weak disturbance enters our area today with light snow expected at all elevations. Snow continues overnight before tapering off Monday.
| Sunday | Sunday Night | Monday | |
|---|---|---|---|
| Cloud Cover: | Cloudy | Mostly cloudy | Overcast |
| Temperatures: | 25 to 30 deg. F. | 15 to 20 deg. F. | 25 to 30 deg. F. |
| Wind Direction: | Southwest | South | Southwest |
| Wind Speed: | 10 to 20, gusting to 30 mph | 10 to 20, gusting to 30 mph | 5 to 15, gusting to 25 |
| Snowfall: | 2 to 4" in. | 2 to 4" in. | 1 to 3" in. |
| Snow Line: | 1500 ft | 2000 ft | 2000 ft |
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.
