Watch for signs of windslab avalanche danger like shooting cracks, especially near ridgetops and in cross loaded gullies. The recent storm snow seems to be most reactive in terrain that was windloaded.
Carefully choose the terrain you play in. A weak, unpredictable layer continues to lurk near the bottom of the snowpack.
Storm totals have been observed at between 15-30 cm in the alpine.
Moderate to strong southwest winds built deeper, more reactive pockets of slab in leeward terrain.
Use extra caution around ridgecrest, rolls, and on convex slopes. Retreat to mellower terrain if you find signs of instability like shooting cracks, whumpfs, or recent avalanches.
The base of the snowpack remains very weak. Avoid thin, rocky start zones and shallow areas with variable snowpack depths.
Deep persistent slab avalanches continue to be reported in this forecast area.
This is a low-probability/high-consequence avalanche problem, and managing it is very tricky.
On Wednesday, west of Golden, small, touchy windslab avalanches were reported. They were triggered remotely from 20 meters away, by skiers skinning along a ridge.
On Tuesday, near Invermere, three natural very large (size 3) storm slab avalanches on south east aspects at 2700 m have been reported. These avalanches had significant debris and in some places had scrubbed to ground and are suspect to have failed on the late November deep persistent slab . Explosive control work conducted near Golden produced three storm slab avalanches, these varied in size from small (size 1) to large (size 2). To the west of the region near the Bugaboos, notable very large (size 4) naturally occurring avalanches have been reported on large north facing alpine bowls that went wall to wall and ran peak to creek.
In the alpine, 15-30 cm of recent snow fell with moderate to strong southwest wind, forming windslabs in leeward terrain.
At treeline, the recent snow is likely to be denser, shallower, and moist or refrozen.
Below treeline, expect to find moist or refrozen surfaces, and shrinking snowpack depths.
The mid snowpack is generally settled and strong, although west of Invermere, some professional operations are still monitoring a layer of weak, feathery surface hoar crystals that was buried in mid January.
The lower snowpack includes a widespread layer of large, weak facets and/or depth hoar crystals. This weak layer has been responsible for several very large and destructive avalanches throughout the season, including one last Thursday.
Unsettled and convective weather could bring brief but intense periods of snowfall. Pinpointing these localized events creates a high level of uncertainty with this weather forecast. Prepare to continually evaluate the conditions, and change plans as necessary.
Thursday Night
Mostly clear. No new snow expected. Freezing level falls to valley bottom. Treeline low around -6°C. Light northwest ridgetop wind.
Friday
Partly cloudy. No new snow expected. Freezing level rising to 1700m. Treeline high around -3°C. Light variable ridgetop wind.
Saturday
Mostly cloudy. No new snow expected. Freezing level at valley bottom overnight rising to 2000 m. Light southeast or southwest ridgetop wind.
Sunday
Mostly cloudy. Possible trace of snow expected. Freezing level at 1300 m overnight rising to 2100 m. Moderate SW wind in the high alpine.
More details can be found in the Mountain Weather Forecast.
