New snow overnight, combined with wind, has increased the hazard. This snow is falling on a variety of surfaces including sun crusts, surface hoar and facets. Fresh wind slab formation is occurring on typical (easterly) leeward aspects. With snow and cold in the forecast now is the time to get your head back into the avalanche game. Carefully evaluate any slope you plan to recreate on. We will continue to issue advisories without a hazard rating until conditions warrant.
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Above 6500 ft.
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5000-6500 ft.
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3500-5000 ft.
24 hour new snow totals as of 0600 range from 2-3" in John F. Stevens Canyon, 4'' at WMR, 7" at Stahl Peak with Noisy Basin in the Swan Range receiving the lions share of this storm with 11" of snow and 1.2" of snow water equivalent. This new snow is falling on a variety of surfaces including surface hoar, facets and sun crusts. Near ridgelines, light winds with moderate gusts are drifting this snow onto leeward aspects and forming fresh wind slabs. Snow and wind throughout today, tonight and tomorrow will continue to redistribute this snow and add thickness to these fresh wind slabs. Evaluate all wind loaded terrain today before committing to a slope. Look for smooth rounded pillows on leeward sides of ridges and cross loaded terrain features. Obvious signs of instability will be cracking, whumphing and hollow sounds. In areas favored by this storm dry loose avalanches on steep terrain will be possible especially on sunny aspects.
Tonight, Thursday December 1, join us at Rocky Mountain Outfitter in Kalispell at 6:30 pm for a free, engaging, and entertaining 1 hour avalanche awareness presentation.
Next Thursday December 8 join us at the Sportsman and Ski Haus in Whitefish for a free 1 hour avalanche awareness presentation.
Remember, avalanches can happen any time of the year. The effect of small avalanches can be amplified by thin snow cover, exposed hazards, and narrow gullies. If there is enough snow to ski or ride, it's deep enough to slide.
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Join the Friends of the Flathead Avalanche Center (FOFAC) and The Patrol Fund for a fundraiser for avalanche education. It's an 80s-themed party with a costume contest, raffle prizes (including skis), and a ton of fun.
Doors open at 8:00 pm.
On Wednesday skiers in Noisy Basin reported moderate winds that were forming 5-10" thick wind slabs on ridgelines. Just below the ridgelines cracking was observed but the slabs were less cohesive. On Tuesday one of these skiers noted a thin layer of facets just above a ice mass 20 cm from the ground. Partial propagation occurred in his ECT on this weak layer.
Mark visited the backcountry outside of the WMR resort on Tuesday. All aspects above 5500' had both a thin layer of surface hoar on the snow surface and a ice mass forming the basal snowpack. Sunny aspects had a thin sun crust just below the surface which failed easily in stability tests. No wind slabs were encountered on this relatively sheltered tour.
Skiers on Saturday ventured outside of our advisory area to Many Glacier on the east side of Glacier Park. They reported little to no snow below 5500 feet with generally 2-4 feet above that. Winds were moderate to strong throughout their tour with many slopes becoming scoured. Most wind slabs that they encountered were stubborn and unreactive but they did note one small slab avalanche.
After several days of sunny above normal temperatures winter has returned to our area. As of 6:00 a.m. temperatures at upper elevation weather stations range from the low to mid 20s F with light winds and light snow. Light snow will continue throughout today and into tonight except for the Swan Range where moderate accumulations are expected. Upper elevation temperatures should top out in the upper 20s F today. Wind speeds are forecast to increase tomorrow with only minor accumulations of new snow and seasonal temperatures.
| 0600 temperature: | 20-26 deg. F. |
| Max. temperature in the last 24 hours: | 20-26 deg. F. |
| Average wind direction during the last 24 hours: | SSW |
| Average wind speed during the last 24 hours: | 5-10 mph |
| Maximum wind gust in the last 24 hours: | 15-25 mph |
| New snowfall in the last 24 hours: | 3-11 inches |
| Total snow depth: | 31-46 inches |
| Thursday | Thursday Night | Friday | |
|---|---|---|---|
| Cloud Cover: | Light snow except for periods of moderate snow in the Swan Range | Mostly cloudy with light snow continuing | Snow tapering with wind speeds increasing |
| Temperatures: | 25-33 deg. F. | 16-25 deg. F. | 23-32 deg. F. |
| Wind Direction: | West | West | Southwest |
| Wind Speed: | 5-8 | 6-8 | 8-10 with gusts 20-25 |
| Snowfall: | 2-5 in. | 1-3 in. | 1-2 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.
