Avalanche Forecast

Issued: Apr 11th, 2019 4:21PM

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

swerner, Avalanche Canada

South Rockies.

The region has received variable storm snow amounts. In areas where 15 cm or more fell you may find reactive wind slabs on northerly aspects in the alpine. Daytime warming and periods of sun will likely trigger loose wet avalanches on solar aspects.

Summary

Confidence

Low - Due to the number and quality of field observations

Weather Forecast

An unstable airmass is mostly responsible for the continued spring-like and (unsettled) weather conditions. Flurries and periods of cloud and sunshine will persist through the forecast period. The convective nature and model disagreement makes it very hard to nail down snowfall amounts.THURSDAY NIGHT: Some cloud cover with possible flurries. FRIDAY: Mix of sun and cloud with a chance of flurries in the afternoon. Alpine temperatures -1 and freezing levels 2100 m. Ridgetop winds light-moderate from the southwest.SATURDAY: Cloudy with snow amounts 5-10 cm. Alpine temperatures near -3 and freezing levels 1900 m. Ridgetop winds strong from the West.SUNDAY: A mix of sun and cloud accompanied by gusty winds. Alpine temperatures near -5 and freezing levels 1700 m.

Avalanche Summary

No new avalanche activity reported from this region on Thursday, the following is from the Lizard Range:On Thursday, explosive control was able to initiate a few loose dry avalanches up to size 1.5 which failed in the recent storm snow. In the afternoon skier controlled loose wet avalanches were easily triggered at treeline and below up to size 1.5 on sunny aspects. No natural avalanche activity was reported and no new avalanches were noted in alpine elevations. Its important to make observations with changing conditions through the day and know when to pull back or dive into your line. If you're unsure, its best to have a conservative approach.

Snowpack Summary

15 cm overnight brings 20-35 cm of recent accumulated snow since the last weekend which sits above a supportive crust at treeline and in the alpine. During the heat of the day, especially under direct sun, the snow surface becomes moist or wet almost everywhere. The exception being high elevation north facing features. Steep, north facing, alpine terrain may still hold a cold, dry, snowpack where isolated reactive wind slabs may exist and a well settled slab rests on weak facets (sugary snow). Although unlikely, human triggering of persistent slabs on this layer may still be possible, especially in rocky alpine terrain with a shallow or highly variable depth snowpack.Below treeline the snowpack is becoming isothermal.

Problems

Wind Slabs

Wind slabs may be reactive to human triggering especially on North facing slopes in the alpine.

Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.

Aspects: North, North East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

The likelihood of loose avalanches increases as temperatures warm through the day and/or if the sun comes out for a period of time. Loose wet avalanches are more likely in areas with fresh snow.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.

Aspects: South East, South, South West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Apr 12th, 2019 2:00PM