Archived

Avalanche Forecast

Apr 8th, 2015–Apr 9th, 2015

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

Regions: Purcells.

Direct sun & warmth are currently the primary drivers of hazard and the weather forecast indicates that Thursday will be quite warm. Minimize your exposure to large slopes if the snowpack is becoming moist or wet.

Confidence

Fair

Weather Forecast

THURSDAY: Freezing level starting near 1500m, rising to around 2200m. Light W/SW winds at all elevations. Clear skies. No significant precipitation expected.FRIDAY: Freezing level starting at 1500m rising to 2100m. Light SW winds at treeline, moderate SW winds at ridgetop. No significant precipitation. Cloud cover rapidly building to overcast by lunch.SATURDAY: Freezing level hovering around 1600m. Moderate SW winds at treeline, Strong SW/W winds at ridgetop. 2 to 4mm precipitation, 2 to 8cm of snow possible. Overcast.

Avalanche Summary

Several cornice falls have been reported in the last few days, some of which have triggered avalanches on slopes below. Small loose wet avalanches running in the storm snow from last weekend have also been observed.

Snowpack Summary

Surface faceting is beginning to work on the 10 to 25cm cm generated by convective snow fall over the weekend. The atmosphere has been unusually calm and wind effect is very isolated. This snow remains dry on high elevation north facing features, but is moist almost everywhere else. Just below this snow you may find tired old wind slabs at upper elevations and the late-March crust. This crust is becoming breakable around 2000m. Moist snow underneath the late-March crust is ubiquitous in most of the region.Persistent weak layers in the mid-pack remain a lingering concern, although they seem to have gone dormant for the time being. In the north of the region, the mid-March crust/facet layer is down 40-60cm and the mid-February crust/facet/surface hoar layer is down about 80 cm. While weak layers formed earlier in the winter remain intact, they too are dormant at this time.

Avalanche Problems

Cornices

Thursday looks to be the warmest day in recent memory. As the mercury rises cornices become more prone to failure. While unlikely, falling pieces of cornice could trigger persistent slab release on slopes below.

When traveling in the alpine, be SURE you're on the ridge, and not on a cornice.>Cornices become weak with daytime heating, so travel early on exposed slopes.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 1 - 5

Loose Wet

Loose avalanche activity should peak Thursday as the freezing level creeps well into the alpine. Loose wet avalanches are possible on all aspects. While slow moving, these avalanches can be very powerful and you do not want to be caught by one.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2