Avalanche Forecast
Issued: Feb 12th, 2020 2:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
jfloyer,
Avalanche Canada
A constant stream of moist air will bring light amounts of new snow with sufficient wind to blow things around. Continue the program: avoid wind slabs on steep slopes.
Summary
Confidence
Moderate - Uncertainty is due to the speed, direction, or duration of the wind and its effect on the snowpack.
Weather Forecast
Wednesday night: 2-4 cm new snow. Moderate southwesterly winds.
Thursday: 3-5 cm new snow. Moderate westerly winds becoming northwesterly in the afternoon. Temperatures around -10 C.
Friday: 2-4 cm new snow. Moderate southerly winds. Temperatures around -12 C.
Saturday: Around 5 cm new snow. Moderate southwesterly winds. Temperatures around -11C.
Avalanche Summary
Since the highway has been closed for avalanche control almost since the last forecast, it is not known whether avalanches occurred in the White Pass area during Monday's storm. While the paths above the highway south of Carcross have a modified snowpack due to avalanche control, significant natural and explosive controlled activity here gives a clue as to what likely happened closer to the Pass.
With relatively light amounts of new snow but ongoing winds, I anticipate human-triggered wind slab avalanches to be of concern throughout the forecast period.
Snowpack Summary
Recent new snow has been redistributed by winds blowing from the south to northwest directions. Wind effect is widespread in exposed areas. Snowpack tests indicate the mid-pack near White Pass is reasonably strong with no persistent weak layers. This suggests the upper storm and wind slab layers should be the main focus of concern at this time. There is reported to be excellent powder and riding in more wind protected / sheltered areas.
Snow depths at White Pass are around 160 cm at our wind protected Fraser study plot. Deeper locations (higher terrain west of the highway) have more than 200 cm, while on the east of the highway depths are around 185 cm. It's reasonable to expect a thin snowpack composed mainly of sugary facets in the Wheaton Valley, and thinner wind-scoured alpine areas.
Terrain and Travel
- Dial back your terrain choices if you are seeing more than 20 cm of new snow.
- Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
- Be carefull around freshly wind loaded features.
- Even brief periods of direct sun could produce natural avalanches.
Problems
Wind Slabs
Recent winds have blown from the south, southwest and northwest. As a result, expect wind slabs to have formed on north-, northeast- and southeast-facing slopes.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Feb 14th, 2020 5:00PM
