Avalanche Forecast
Issued: Mar 8th, 2017 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
stephen holeczi,
Avalanche Canada
Avalanche control on Mt. Stephen and Mt. Field in Yoho, and Mt. Hector on Hwy 93N Thursday, March 9. No activities in these areas during that day.
Summary
Weather Forecast
Light winds and -10C at treeline with only a trace of snow for Thursday. Friday another pulse of snow (10-12mm) along the divide and increased alpine winds into the moderate to strong range.
Snowpack Summary
50-70cm of storm snow has developed into a storm slab that is reactive at treeline and above. This sits over a mainly settled snowpack, especially closer to the Wapta where 225cm was found at 1800m near Tak Falls. In some areas there is a facet layer down 70-80cm below 2000m that has gained strength, and well bridged rounding facets below.
Avalanche Summary
Over the last few days there have been many larger than expected avalanches to size 3 within the storm snow from avalanche control as well as naturals. Some have been seen to step down to the deeper weak layers.
Confidence
Problems
Storm Slabs
A 50 - 60 cm storm slab has been very reactive in recent avalanche control, and this slab appears to be widespread. Fracture lines have been spreading into adjacent terrain, so mind your exposure carefully.
- Be aware of the potential for wide propagations.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Several buried weak layers in the middle of the snowpack are gaining strength over time as they become bridged, especially in the deeper areas closer to the Wapta. Dig down to see if they are present on your line, and how they are reacting.
- Dig down to find and test weak layers before committing to a line.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 9th, 2017 4:00PM
