Avalanche Forecast

Issued: Mar 22nd, 2018 3:13PM

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

swerner, Avalanche Canada

South Rockies.

Storm slabs will likely be reactive to skier and rider triggers. Changing winds from the East to the Southwest will potentially form wind slabs on most aspects.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Overnight Thursday: New snow 5-10 cm accompanied by strong southwest winds and freezing level at valley bottom.Friday: Cloudy with sunny periods. Snow 5 cm possible, but low confidence on actuals. Ridgetop wind strong from the southwest. Alpine temperatures near -2 and freezing levels 1500 m.Saturday: Mostly cloudy. Snow amounts near 5-10 cm and ridgetop wind strong from the southwest. Alpine temperatures near -3 and freezing levels 1500 m.Sunday: Mix of sun and cloud. Freezing levels near 1300 m. Ridgetop wind mostly light with strong gusts from the southwest.

Avalanche Summary

No new avalanche observations from this region.Avalanche hazard will be on the rise with forecast snow and wind.

Snowpack Summary

Up to 5 cm of new snow adds to the 30 cm from earlier this week. Forecast snow for Friday will add to these totals and likely have a poor bond to the underlying snow surfaces which consist of crusts, dry snow or surface hoar on north aspects above 1500 m. Deeper in the snowpack (50-80 cm down) a weak layer of surface hoar buried mid-February may exist. This interface is dormant, but could wake up with a heavy load like a cornice fall, human triggers from a thin, shallow area on the slope or a rapid warm up. Digging towards the bottom of the snowpack you'll find a combination of crusts and facets that are reportedly widespread.

Problems

Storm Slabs

The new snow will likely have a poor bond to the plethora of old snow surfaces. Especially where it sits on the March 18th crust and surface hoar. Changing winds will likely build wind slabs on numerous aspects.

Watch for signs of instability such as whumpfing, or cracking. Use caution in lee areas in the alpine and tree line, especially north/ east facing slopes.Avoid large slopes with thin-thick snow coverage and convex features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Valid until: Mar 23rd, 2018 2:00PM