Avalanche Forecast

Issued: Apr 9th, 2019 4:31PM

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.

An unsettled weather pattern exists through the forecast period. Expect new snow (if any) and strong wind to form isolated wind slabs in the alpine and loose wet avalanches at lower elevations with daytime warming and periods of sunshine.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Wednesday

Weather Forecast

The region will see a fairly unsettled weather pattern through the forecast period. Convective spring-like conditions could bring pulses of new snow in some areas or none in others. TUESDAY NIGHT: Light snow amounts 3-10 cm at upper elevations and freezing levels 1300 m. Ridgetop winds light from the NE.WEDNESDAY: Cloudy with some sunny periods and light snow 0-5 cm. Alpine temperatures -1 and freezing levels 2200 m. Ridgetop winds 10-30 km/h from the West.THURSDAY: Cloudy with some sunny periods and a trace of snow. Alpine temperatures near -3Â and freezing levels 1900 m. Ridgetop winds light from the southwest.FRIDAY: A mix of sun and cloud. Alpine temperatures near -2 and freezing levels 1900 m. Ridgetop winds light with strong SW gusts.

Avalanche Summary

No new avalanche activity reported from this region, the following is all from the neighboring Lizard Range and Flathead region: On Tuesday, numerous natural loose wet avalanches up to size 1.5 occurred mostly from sunny aspects. With spring conditions, the avalanche hazard will fluctuate greatly depending on the strength of the overnight re-freeze and how quickly the snowpack is warmed up.

Snowpack Summary

Sunday night the region picked up 5 to 10 cm of moist snow which turned to shmoo from the warmer temperatures during the day. This snow rests on a supportive crust above about 1400 m. Below 1400 m the snowpack is becoming isothermal. 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 a well settled slab rests on weak 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.

Problems

Wind Slabs

Wind slabs may be reactive to human triggering especially on North facing slopes at upper elevations.

Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.Be alert to conditions that change throughout the day.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 prolonged 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: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 1.5

Valid until: Apr 10th, 2019 2:00PM