Avalanche Forecast

Issued: Apr 21st, 2018 4:40PM

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

jsmith, Avalanche Canada

South Rockies.

Sunshine and warming temperatures throughout the week will increase the likelihood of cornice failures which have the potential to trigger large avalanches on deeply buried weak layers.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

SUNDAY: Mix of sun and cloud. Light west wind. Alpine temperature -2. Freezing level 2100 m.MONDAY: Sunny. Light southeast wind. Alpine temperature +2. Freezing level rising to 2500 m.TUESDAY: Sunny. Light southwest wind. Alpine temperature +6. Freezing level rapidly rising to 3200 m.

Avalanche Summary

No new avalanches were reported in this region. Avalanche reports have been limited due to very few information sources this time of year. If you have been out, please post your observations on the Mountain Information Network (MIN).

Snowpack Summary

Cornices are large and looming. Flurries and strong westerly winds may have formed small wind slabs at treeline and above. Below the surface there are numerous crusts in the upper 100 cm of the snowpack.A well settled and moist mid-pack sits above sugary facets in many parts of the region, especially thin snowpack areas.

Problems

Cornices

Sunshine and warming temperatures will increase the likelihood of cornice fall.

Falling cornices may trigger persistent weak layers deeper in the snowpack.Cornices become weak with daytime heating. Give them a wide berth both from above and below.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Loose Wet

When the sun comes out it will quickly weaken the new snow and cause loose wet avalanches on steep solar slopes.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Watch for signs that the snow is heating up such as pin-wheeling or the surface snow becoming moist.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Wind Slabs

Flurries on Saturday may form small wind slabs on leeward slopes below ridgetops.

Avoid areas that look freshly loaded with snow; especially convex features below ridgetops.Use caution when transitioning into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Apr 22nd, 2018 2:00PM