Today's danger will start out at LOW. As temperatures rise and the clouds break up, the avalanche danger will rise to CONSIDERABLE on sunny slopes above 6000 feet. The upper elevation snowfall from earlier this week has yet to be tested by the spring's powerful daytime warming and sunshine. As the sun heats the snow surface, move to shadier slopes. The danger will rise to MODERATE in the mid-elevations, where it will remain possible to trigger loose, wet avalanches.
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Above 6500 ft.
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5000-6500 ft.
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3500-5000 ft.
Spring warming and increasing solar radiation will heat the snow surface and increase the avalanche danger throughout the day. Human triggered avalanches will be likely above 6000 feet on sunny aspects as the day progresses. With clearing skies and warming temperatures, be aware of rapidly changing surface conditions. Rollerballs and glopping snow to skis and snowmobiles are indicators of weakening snow surface. Avoid consequential terrain as a small loose, wet avalanche could knock you off your feet or snowmobile and push you into a bad spot.
Massive cornices exist along many of the ridgelines across the advisory area. Warming temperatures and sun exposure could weaken these features today. It's important to pay attention to what is suspended above you given the unusual size and how overhung many of these cornices are. Keep a good distance from these while traveling along ridge lines as they can pull out further back than expected, even behind the solid ground. When a large cornice falls it has the potential to trigger deep instabilities that would otherwise remain dormant resulting in a large avalanche.
In the true alpine, where winter has held on to its cold temperatures and blustery winds, wind slabs still linger. Although off the problems list, there has been enough dry looose snow available for transport above 6500 feet, recently, to continue to form fresh wind slabs. Near the Continental Divide, we've had reports and seen thin but widespread wind-slabs still forming. As spring skiing missions take you higher into the mountains be cautious where winter still remains.
he wet slab cycle we saw in mid-March due to high rain levels was impressive, but I don't think we have seen the last of them. Most of these avalanches occurred in the mid-elevation band. Though we did see some storm slab activity in the high elevations the upper snow pack absorbed most of the free-water before it could pool on deeper crusts. With the fickle and often surprising weather events that Spring in northwest Montana brings it's important to pay attention to conditions that could weaken these deep layers again. Like extended periods of warm and sunny weather and rain that soaks the snow at higher elevations.
Glide cracks have also been observed opening up in many locations. The first reported glide avalanche this season was March 25 and occurred west of the WMR ski area in the southern Whitefish Range. There is a large amount of uncertainty associated with glide avalanches, so the best way to manage them is to avoid slopes where they are present.
Thursday: Skiers in the Red Meadow area reported multiple small wet slides on sunny aspects and a breakable crust up to 6000 feet. At 7200 feet they found 10 inches of fresh snow. They observed a rapidly changing snow surface with the input of direct sunshine.
Wednesday: FAC staff rode into the Skyland area and observed active wind loading, but with little snow to tranport as windward slopes were nearly scoured. They saw a recent wind slab avalanche triggered by cornice fall on the east face of Slippery Bill Mountain.
See below for all observations this season.
Our most recent system tapered off yesterday, leaving up to an inch of new snow at high elevations last night as it retreated. Yesterday, temperatures at 6000' climbed to over 40º F and light winds shifted from the southwest to the north. Currently, mountain temperatures are 28-33º F and winds are 2-8 mph gusting to 18 mph out of the north/northeast. Today expect partly cloudy and clearing conditions with temperatures rising to the mid-upper 30s. Winds should be light from the northeast, but shifting back to our usual southwest flow by this evening.
| 0600 temperature: | 27-33 deg. F. |
| Max. temperature in the last 24 hours: | 35-42 deg. F. |
| Average wind direction during the last 24 hours: | SW shift N |
| Average wind speed during the last 24 hours: | 5-10 mph |
| Maximum wind gust in the last 24 hours: | 10-20 mph |
| New snowfall in the last 24 hours: | 0-1 inches |
| Total snow depth: | 85-123 inches |
| Friday | Friday Night | Saturday | |
|---|---|---|---|
| Cloud Cover: | Partly cloudy and clearing throughout the day | Clear and calm with clouds returning | Mostly cloudy with precip possibly returning |
| Temperatures: | 36-51 deg. F. | 21-30 deg. F. | 35-51 deg. F. |
| Wind Direction: | East - Northeast | Southwest | Southwest |
| Wind Speed: | 4-6 gusts to 15 | 4-6 gusts to 16 | 9-11 gusts to 26 |
| Snowfall: | 0 in. | 0 in. | 0 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.
