North Columbia Avalanche Forecast

Mar 21st, 2020 4:00PM

The alpine rating is low, the treeline rating is low, and the below treeline rating is low. Known problems include Loose Wet.

A low pressure system is due to move in by late afternoon. Clouds, cooler temperatures, and snow are on the way. Low hazard doesn't mean no hazard. Make observations and assess conditions continually.

Summary

Confidence

High - Confidence is due to a stable weather pattern with little change expected.

Weather Forecast

Saturday night: Mostly clear, light southwest wind, alpine temperature -12 C, freezing level valley bottom.

Sunday: Increasing cloud, isolated flurries in the afternoon with trace accumulations, light southwest wind gusting moderate at ridge-tops, alpine temperature -6 C, freezing level 1300 m. 

Monday: Mostly cloudy, 5-15 cm of snow, light west wind, alpine temperature -7 C, freezing level 1300 m.

Tuesday: Mostly cloudy, 5-10 cm of snow, light southwest wind, alpine temperature -8 C, freezing level 800 m. 

Avalanche Summary

Over the past several days, avalanche activity was reported as natural loose dry or loose wet avalanches size 1-2 running in steep, sun-exposed terrain. One large (size 2) slab avalanche released naturally as a result of strong solar radiation on a south aspect at 2500 m. There were also several large cornice failures on northerly aspects (up to size 2.5).

If you decide to travel in the backcountry, consider sharing your observations via the Mountain Information Network (MIN) to supplement our data stream as operators are shutting down. A conservative mindset and margins are recommended at this time.

Snowpack Summary

With snow on the way, Sunday's surface conditions will comprise the next interface. Recent reports indicate that conditions are highly variable with a mix of sun crusts, moist snow, hard wind slabs, and soft faceted snow. Observers have noted that surface hoar may be forming on sheltered, shady slopes. These conditions will be important to track across aspects and elevations if you're spending time in the mountains on Sunday.

Cornices are large, looming, and weakening with warm temperatures and strong solar radiation.

A widespread weak layer of surface hoar buried in late February is now 60-100 cm deep. Sheltered north, northeast, and east facing slopes near treeline are the most likely locations to find this layer. Avalanche activity on this layer was last reported on March 8th.

Terrain and Travel

  • Back off slopes as the surface becomes moist or wet with rising temperatures.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
  • Make observations and assess conditions continually as you travel.

Problems

Loose Wet

An icon showing Loose Wet

Likelihood

Unlikely-Possible

Expected Size

1 - 1.5

Small loose dry or wet avalanches are possible in steep terrain facing the sun during the heat of the day. Cornices may also warm and weaken and could act as triggers for large slab avalanches.

Aspects:

South East, South, South West, West.

Elevations:

All elevations.

Valid until: Mar 22nd, 2020 5:00PM