Avalanche forecast

Northwest Inland

Feb 10, 2017Avalanche Canada
View on map
Archived · expired 10 years ago

Avalanche danger

Fri
Sat
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
Open full map

Highlights

Use extra caution as you transition into wind affected terrain

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–2
    Recent strong to extreme outflow winds have formed hard wind slabs in leeward terrain features. These slabs are expected to remain reactive as the wind may continue to add additional load to these slabs.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–4
    A weakness at the bottom of the snowpack is lingering. This layer may be triggered in shallow snowpack areas or by the weight of smaller avalanches.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

FRIDAY: Mix of sun and cloud / Moderate to strong southwest wind / Alpine temperature -9SATURDAY: Cloudy with isolated flurries / Moderate to strong southwest wind / Alpine temperature -7SUNDAY: Cloudy with isolated flurries / Moderate to strong southwest wind / Alpine temperature -4More details can be found on the Mountain Weather Forecast.

Avalanche Summary

On Friday, expect recently formed wind slabs to remain reactive to human triggering. Ongoing outflow winds may continue to add additional load to these wind slabs in places where there is still snow available to be redistributed. A basal weakness continues to drive a low probability/high consequence problem for the region. Very large avalanches remain possible, especially in shallow snowpack areas.No new avalanches were reported in the past few days. Most recent avalanche activity was reported last weekend, which included a remotely triggered size 2 avalanche and naturally triggered avalanches to size 2.5. Some of the natural avalanches involved the full depth of the snowpack.

Snowpack Summary

Widespread wind affected surfaces are being reported in exposed terrain including scoured surfaces, sastrugi, and hard wind slabs. In areas sheltered from the wind, the surface snow is reported to be faceting and surface hoar is developing. Below around 1400 m elevation, a rain crust can be found near the surface of the snowpack. Deeper in the snowpack, several buried surface hoar layers can be found between 30-70 cm deep. Recent reports suggest these layers have generally stabilized but isolated weaknesses may still exist, especially where buried surface hoar is still intact. A generally stiff mid pack sits above weak sugary snow near the ground. This basal weakness woke up during the last storm and produced numerous large avalanches which released on the ground. The layer is dormant for the time being but is expected to wake up with warming, heavy loading, or by the weight of a smaller avalanche stepping down.

Regions covered