Archived

Avalanche Forecast

Apr 9th, 2019–Apr 10th, 2019

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

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

Regions: Purcells.

Wind has developed slabs around ridges and in lee features at upper elevations. If the sun comes out and temperatures rise, the likelihood of loose wet avalanches will increase as the snowpack warms.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

TUESDAY NIGHT - Cloudy with scattered flurries, trace to 5 cm / northwest winds, 10-20 km/h / alpine low temperature -3 C / freezing level below 1500 mWEDNESDAY - Cloudy with sunny periods and isolated flurries, up to 5 cm / west wind, 10-25 km/h / alpine high temperature -1 C / freezing level 1900 m THURSDAY - Cloudy with sunny periods and scattered flurries, 5-10 cm / northwest wind 10-25 km/h / alpine high temperature -4 C / freezing level 1700 mFRIDAY - Mix of sun and cloud / north wind 10-20 km/h / alpine high temperature -1 / freezing level 2000 m

Avalanche Summary

On Saturday, there were a few reports of natural and human triggered wind slab avalanches, mainly in the alpine on north and east facing slopes.On Sunday, small (size 1-1.5) wind slabs were reactive to skiers, generally around ridge crests and steep, convex terrain above 2200 m. The most reactive deposits were in immediate lee features, including a size 2 wind slab avalanche remotely triggered from a rocky saddle 10 m away. Overnight Sunday, a natural avalanche cycle to size 2 occurred on the western side of the Purcell Forecast region. Storm slab avalanches were observed on steep alpine slopes on all aspects.

Snowpack Summary

Recent storm snow sits on a melt-freeze crust on all aspects except for north slopes above 2000 m, snow remains dry. Southwest winds developed wind slabs around ridges and exposed treeline features and into the alpine. Below 1200 m, snow is disappearing rapidly.The base of the snowpack is composed of sugary faceted snow. The likelihood of triggering an avalanche on this layer is lower during colder periods and elevated during intense warming.

Avalanche Problems

Loose Wet

As temperatures rise and the snowpack warms during the day, the likelihood of loose wet avalanches will increase, especially in areas with fresh snow.

Use extra caution on slopes if the snow is moist or wet.Avoid sun exposed slopes and overhead exposure during periods of intense sun.

Aspects: East, South East, South, South West, West.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2

Wind Slabs

Wind has redistributed recent snowfall forming wind slabs around ridge crests and lee-terrain at treeline and into the alpine.

Use extra caution on slopes if the snow is moist or wet.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: North, North East, East, North West.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 1.5