Archived

Avalanche Forecast

Mar 20th, 2014–Mar 21st, 2014

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Kootenay Boundary.

Watch the temperature and solar warming! Heat and cornices are two great ways to shake-up the snowpack over the next couple of days.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Thursday night and Friday: Light flurries with a mix of sun and cloud / Light to moderate northwest winds / Freezing level at 800mSaturday: Flurries with a mix of sun and cloud / Light to moderate northwest winds / Freezing level at 800mSunday: Flurries with a mix of sun and cloud / Light to moderate northwest winds / Freezing level at 1200m

Avalanche Summary

Although observations were limited, I expect there would have been a round of storm slab activity in response to new snow and wind on Thursday. Looking forward, forecast sunshine may spark a loose wet avalanche cycle.

Snowpack Summary

In general about 35cm of new snow fell on Thursday adding to an existing storm slab which formed last weekend. Wind data was scarce on Thursday, although I suspect the new snow exists as a wind slab in exposed lee terrain. Below the recent storm snow you may find weak surface hoar in shaded terrain and a crust on previously sun-exposed slopes. About 60cm below the surface you'll find a strong rain crust which exists on all aspects below 2000m. This crust is widespread in the south of the region where heavy rain fell on March 10. As you head north in the region where the mountains are higher and colder temperatures persisted, this crust is less likely to exist.A facet/crust persistent weakness buried at the beginning of February, now down 70 to 160cm, has been highly variable in terms of reactivity but still shows 'sudden' results in some snowpack tests. In areas where the strong and supportive near surface crust exists, triggering this layer has become unlikely. That said, this layer is still difficult to trust and any avalanche at these deeper, persistent interfaces would be large and destructive.,

Avalanche Problems

Storm Slabs

Up to 35cm of new snow fell on Thursday adding to an existing storm slab which may be touchy in wind exposed terrain.

Be aware of the potential for buried surface hoar, and crusts (on solar aspects).>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Loose Wet

Watch for loose wet avalanches in steep, sun-exposed terrain. Loose wet avalanches can be pushy and entrain mass quickly.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Avoid exposure to terrain traps and cliffs where the consequences of a small avalanche could be serious.>

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

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3

Deep Persistent Slabs

The deeply buried weak layers still show "sudden" results in snowpack tests. Triggers for large avalanches on these layers include cornice falls, solar warming, or hitting the wrong place in a thin snowpack area.

Caution around slopes that are exposed to cornices overhead.>Avoid convexities or areas with a thin or variable snowpack.>Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 3 - 5