Weak snow (facets) at the ground and wind slabs atop a crust near the surface continue to create unstable conditions. Conservative decision making and terrain selection are important with a weak and shallow early season snowpack. We will begin issuing regular advisories Saturday, Dec. 6.
?
Above 6500 ft.
?
5000-6500 ft.
?
3500-5000 ft.
Within the previous week a lot has happened to the snowpack. The warm temperatures and rain around Thanksgiving created a crust that now exists in the middle third of our snowpack. The post-Thanksgiving storm dropped new snow on this crust and created wind slabs in some locations. Underneath this new snow/wind slab now lies a thin layer of facets above the crust that showed signs of instabilty in our stabilty tests last Saturday. Others also reported this new snow to fail on the top of this crust.
The constant through all of this change has been the weak snow (facets) at or near the ground. This layer shows signs of instability in stability tests (video) and should be treated as suspect. Only time will tell if this layer strengthens as more mild weather enters the region. Until then, dig down into the snow to identify this layer and avoid slopes where this layer exists. The snowpack is still relatively shallow (3-4 feet deep) and digging down to the ground takes very little time.
Allow the snowpack time to adjust, and remember that it may take a few days or more for this to occur. Always carry your avalanche gear (beacon, shovel, and probe) with you. Look for obvious signs of instability like recent avalanche activity, cracking of the snowpack, and whumpfing (collapsing). Also, with a shallow early season snowpack any avalanche (even a small one) could take you for a nasty ride over rocks and stumps. Ask yourself if early season turns or riding is worth it before committing to any steep slope.
We are currently in the field getting a handle on the snowpack. We need more data before we begin issuing hazard ratings and regular advisories with avalanche problems. We intend to issue our first advisory December 6, and, until then, will provide updates as conditions warrant. We greatly appreciate all of the observations thus far this season. If you are out in the backcountry continue to send us your observations by submitting them on the Observations page, emailing us at [email protected], or by calling 406.387.3835.
Yesterday, we rode into the Skyland/Challenge Creek area in the Flathead Range. We found about 8-12 inches of light, new snow on top of a thick crust (Thanksgiving crust). Unfortunately, we also found weak snow (facets) at the ground (image and video). This layer collapsed and propagated fractures in all of our stability tests throughout the day on numerous slopes and aspects. This layer at the ground also existed in our snowpits on Big Mountain last Saturday. Other public observations reported similar snowpack conditions in Canyon Creek/Flower Point in the southern Whitefish Range.
We also found sensitive wind slabs on Big Mountain last weekend and other reports from the southern Whitefish Range indicate these wind slabs exist in other locations.
Cold temperatures, moderate to strong wind, and minor accumulations of snow dominated the past 48 hours since the last storm. Temperature inversions should exist today with colder valley air and slightly warmer mountain air and clearing over most locations. Temperatures should warm at mountain locations over the next 48 hours with only snow flurries expected.
| 0600 temperature: | 6-15 deg. F. |
| Max. temperature in the last 24 hours: | 10-18 deg. F. |
| Average wind direction during the last 24 hours: | SW |
| Average wind speed during the last 24 hours: | 10 mph |
| Maximum wind gust in the last 24 hours: | 27 mph |
| New snowfall in the last 24 hours: | 1-5 inches |
| Total snow depth: | 14-46 inches |
| Tuesday | Tuesday Night | Wednesday | |
|---|---|---|---|
| Cloud Cover: | Drier air moves into region today. | Mostly clear skies. | Weak ridge builds into region bringing mostly clear skies. |
| Temperatures: | 14 to 23 deg. F. | -15 to 7 deg. F. | 20 to 28 deg. F. |
| Wind Direction: | W | SW | SW |
| Wind Speed: | 10-15 | 10-15 | 10-15 |
| Snowfall: | 1 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.
