Archived

Avalanche Forecast

Apr 17th, 2017–Apr 18th, 2017

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

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

1: Low

The avalanche danger rating at treeline will be low

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

Regions: South Rockies.

Winter weather continues to bring snow to alpine elevations and rain below treeline. Expect avalanche danger to increase during the warmest part of the day.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Overnight: A couple of cm of new snow with moderate to strong southwest winds and freezing down to 1500 metres. Tuesday: Convective flurries during the day and then 3-5 cm of snow in the evening combined with moderate west winds and daytime freezing up to 2100 metres. Wednesday: Mostly sunny with moderate southwest winds and daytime freezing up to 2100 metres. Thursday: Mostly cloudy with periods of broken skies, light winds, and daytime freezing up to 2400 metres.

Avalanche Summary

Recent reports indicate several natural storm slab and cornice triggered avalanches to size 2 on all aspects tree line and above. Exposure to large overhanging cornices remains a significant concern.

Snowpack Summary

Moist new snow falling last week above tree line has been redistributed by south and southeast winds. Cornices remain large and continue to become more overhanging. The middle of the snowpack is generally well settled and continues to transition into a spring melt/freeze regime. Expect the entire thickness of the snowpack to be moist or wet at lower elevations. At upper elevations, the bottom third of the snowpack is composed of weak facets, however there still is uncertainty to this layer's reactivity. That being said, a heavy load like a cornice fall or rapid warming of the snowpack could potentially trigger this layer.

Avalanche Problems

Cornices

Cornices are most likely to trigger during periods of intense sunshine and/or the warmest parts of the day.

Give cornices a wide berth when traveling on or below ridges.Cornices become weak with daytime heating and/or rain.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 2 - 3

Loose Wet

Loose wet avalanches are more likely during periods of strong solar radiation and/or daytime warming. The days are getting longer, and the warmest part of the day may be in the late afternoon.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

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

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2