Avalanche Forecast

Issued: Mar 14th, 2021 4:39PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Loose Wet, Wind Slabs and Deep Persistent Slabs.

timothy johnson,

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Watch out for rising temperatures and solar heating which can increase the avalanche danger. Start early.

Summary

Weather Forecast

Monday: Cloudy with sunny periods. Alpine temperature: High -4 °C. Ridge wind light to 15 km/h. Freezing level: 1700m

Tuesday: A mix of sun and cloud. Alpine temperature: Low -10 °C, High -5 °C. Light ridge wind. Freezing level: 1600m

Snowpack Summary

Sunny skies and warm temperatures have created crusts and moist snow on solar aspects at tree line and below. There is widespread wind scouring to rock in exposed alpine features. The middle of the snowpack is supportive in deep areas but weak in shallow spots where it fails on buried facet layers in test results.

Avalanche Summary

Several natural wet avalanches crossed the highway 93N on Sunday near Weeping Wall from below tree line slopes.  Natural and explosive triggered avalanches stepping down to the February persistent weak layer (down 60cm) resulted in two size 2 avalanches at Marmot Basin.

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Loose Wet

An icon showing Loose Wet

Even with clouds in the forecast, green house effect and higher freezing levels have the potential to warm up the snowpack enough for the wet loose to be an issue. Best time to travel is early while its frozen solid.

  • Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: South, South West, West.

Elevations: Treeline, Below Treeline.

Likelihood

Likely

Expected Size

1 - 1.5

Wind Slabs

An icon showing Wind Slabs

Originally formed on weak Feb 20th facets. It is prudent to keep this on your radar with warmer temperatures as reactivity may increase. Cornices will have the potential to fail and trigger slabs below.

  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
  • Pay attention to overhead hazards like cornices which could trigger slabs.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Caution in thin facetted snowpack areas where triggering is more likely. This is a low probability but high consequence problem.

  • Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Valid until: Mar 15th, 2021 4:00PM