Be aware in the backcountry

Details thin at this time of year, but avalanches possible

This early in the year, it is difficult for forecasters at Avalanche Canada to post exact avalanche danger ratings, but that doesn’t mean the danger isn’t there. The problem is that the winter backcountry recreation season has just begun and there are not enough snowpack observations collected as yet.

However, according to avalanche.ca it may be early in the season, but there is more than enough snow for avalanches. Avalanche Canada has launched the Mountain Information Network, so that you can submit your observations on snow conditions through your smartphone. If you can take the time to dig a snow pit and observe, all the better. All this information assists in forecasting avalanche danger.

But while there are not ratings posted yet, there are some observations and forecasts. For those of you who intend to get out in the backcountry this weekend, here are the first forecasts from avalanche.ca.

For the South Rockies:

Snowpack observations have been very limited as the season commences. Initial reports suggest that there is enough snow above around 1700m for avalanches to occur. Around 10cm of new snow sits on a thick rain crust which exists to at least treeline elevation. In exposed terrain at higher elevations, new winds slabs are expected to have formed and may linger for a few days until temperatures warm up. The stiff underlying crust may increase the likelihood of triggering a wind slab avalanche.

The cold and dry Arctic air persists on Thursday. Freezing levels should stay well below valley bottom and alpine winds should be light from NE. On Friday afternoon, a layer of warm air aloft should reach the region. Above freezing temperatures should develop around 2000m while the valleys remain cold. Valley fog may develop on Friday and should definitely be established by Saturday. Dry, sunny, and warm conditions are expected to persist at higher elevations at least through the weekend.

For the Purcells:

One operator produced a size 2 avalanche with explosives on a N slope at 2300m. There have also been reports of skier controlled size 1’s, 15 to 20cm storm slabs failing on the Nov 23rd surface hoar

Snowpack Summary

Monday’s storm snow fell on a variety of old surfaces including crust, surface hoar and old settled snow. Arctic air moving into the region has resulted in northerly winds which have formed small wind slabs on south facing features near ridge top. Warm temps and strong solar input formed a crust on south facing features which can be found underneath Monday’s storm snow. There are at least three surface hoar layers in the snowpack buried on: Nov. 5th, Nov. 11th and Nov. 23rd. The first two have been largely unreactive. Facets may exist just above the ground on shaded slopes in the alpine.  Warming temperatures  in the alpine for later in the week may significantly change the alpine hazard

For Kootenay Boundary:

On Wednesday, ski cutting and explosives triggered several wind slab avalanches up to size 1.5.  The avalanches are sliding on a firm rain crust from mid-November.  Slabs were typically 5-15cm thick and were reported on a variety of aspects.  These types of wind slabs may persist for a few days until temperatures warm up at higher elevations.

Snowpack Summary

10-20cm of new snowfall overlies a highly variable surface which may include surface hoar and/or facetted snow, a thick rain crust which exists to at least treeline elevation, a sun crust on steep south facing slopes, or wind-affected snow in exposed alpine terrain. At treeline elevations, the snowpack appears to typically be 1-1.5m deep. There is a thick crust from early-November in the middle of the snowpack. The limited reports we have received suggest that this crust is well bonded but you should investigate the snowpack in your local area before committing yourself to avalanche terrain. Wind slabs exist on a variety of aspects due to shifting winds may persist for a few days while temperatures remain cold.

 

Kimberley Daily Bulletin

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