North Columbia Avalanche Forecast

Mar 23rd, 2020 4:00PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs.

Watch for the formation of wind slabs in high elevation terrain.

Summary

Confidence

Low -

Weather Forecast

MONDAY NIGHT: Freezing level at valley bottom, light variable wind, a few centimetres of snow possible.

TUESDAY: Overcast, freezing level rising to about 1000 m, light west/southwest wind, a few centimetres of snow possible.

WEDNESDAY: Scattered cloud cover, freezing level around 1000 m, light west/northwest wind, no significant snowfall expected.

THURSDAY: Scattered cloud cover, freezing level around 1400 m, moderate west/southwest wind, no significant snowfall expected.

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).

Snowpack Summary

1 to 5 cm fell across the region Sunday with light variable wind, but moderate gusts at ridge-top may be forming shallow wind slabs.

The new snow is falling on a variety of snow surfaces, consisting of sun crusts, hard wind-affected snow, and soft faceted snow. There have also been reports of surface hoar forming on sheltered, shady slopes. See this MIN for a helpful illustration from nearby Glacier National Park. It will be important to track the depth, cohesiveness, and bond of the new snow to these various old snow surfaces across aspects and elevations where you're travelling.

Cornices are large and looming. Two layers of buried surface hoar may be found buried 20-40 cm deep (March 10) and 60-120 cm deep (February 22). Though there is a low likelihood of triggering an avalanche on these layers, the consequences of doing so would be high. Avalanche activity on the Feb 22 layer was last reported on March 8th.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Make observations and assess conditions continually as you travel.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 1.5

Watch for wind slabs in high elevation terrain.

Aspects:

North, North East, East, South East, South, West, North West.

Elevations:

Alpine.

Valid until: Mar 24th, 2020 5:00PM