Thursday, February 6th 2014 6:52 am by Kevin Wright
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
The general avalanche hazard is LOW in the majority of the forecast area. A thick surface crust is keeping the snow “locked up” in all but the highest elevation starting zones.
In high elevation steep terrain, the possibility exists for triggering an old wind slab or a deep slab avalanche. In these areas the avalanche hazard remains MODERATE.
A serious concern in the mountains around Eastern Turnagain Arm remains “slide for life” conditions, especially in steep terrain below 3,500’. Slick, hard crusts are making it very difficult to arrest a fall.
|Show the Complete North American Avalanche Danger Scale|
|Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.|
|Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.|
Are you interested in contributing to backcountry avalanche research? The University of Montana is collecting data from around the world and needs your help. Participation is simple, and anyone with a GPS or smartphone can contribute. Go to www.montana.edu/snowscience/tracks for more information on this project.
In terrain above 3,500’, the last storm cycle laid down mostly snow (as opposed to rain). Terrain above this elevation is harboring old wind slabs up to a foot in depth. These slabs are resting on weak interfaces. It is on steep upper elevation leeward slopes where you are most likely to encounter unstable snow today. The likelihood of triggering an old wind slab is on the lower end of the scale but cannot be ruled out.
We got a good observation from the Divide creek area yesterday. A shallow layer of facets is somewhat reactive to pit tests. Same for the well developed facets at the ground. Overall these are only moderate concerns, but should be taken into consideration when out in the backcountry.
Slabs 3-6 feet thick are sitting on weak snow near the ground in the upper elevations. It is less likely to trigger a deep slab today in comparison to a more shallow old wind slab or persistent slab. However, the possibility remains for triggering a slab that can pull out snow to the ground. Unlike the persistent (old) wind slab concern, deep slabs have the potential to move large volumes of snow. Avoiding likely trigger points, especially areas where slabs are thinner, will lower the likelihood of triggering a deep slab avalanche today.
This problem is not a concern below 3000 feet where the previously water saturated layers have now frozen into a very strong and stable crust layer.
In case you’re just tuning in, we have a very thick crust in the forecast area. This "bulletproof" crust exists on all aspects up to 3,500’ in elevation, and is over 2 feet thick in places. Travel in steep terrain warrants extra caution, as arresting a fall is very challenging at this time.
Expect all of these issues to remain until a shift in the weather pattern takes place and surface conditions change.
Clear skies, light wind, and average winter temperatures (20s F) have been the weather over the last couple days. This trend will continue through today and transition to something a little different this evening.
The National Weather Service is issuing a Winter Weather Advisory for Friday morning to Saturday morning for blowing snow that may reduce visibility and make travel difficult. This is due to a forecasted 2-6 inches of cold dry snow with moderate to strong wind.
This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).
Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.
(Updated: Jan 13, 2019 )
|AREA||STATUS||WEATHER AND RIDING CONDITIONS|
|Twentymile:||Closed||Closed. Forest Service is monitoring conditions.|
|Lost Lake Trail:||Open||Please stay on trail to avoid resource damage through forested areas.|
|Primrose Trail:||Open||Please stay on trail to avoid resource damage through forested areas.|
|Resurrection Pass Trail:||Closed||Closed for the 2018/19 season. Next season will be open to motorized use.|
|South Fork Snow River Corridor:||Open|
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