Warm weather and strong sunshine is very likely to set off loose snow avalanches, particularly on southerly aspects.
Summary
Confidence
High -
Weather Forecast
TUESDAY NIGHT: Flurries with no significant accumulation expected.WEDNESDAY: Dry and sunny. Freezing level around 1600 m. Moderate easterly winds up to 30 km/h.THURSDAY: Dry and sunny. Freezing level around 1600 m. Winds light southeasterly, becoming calm in the afternoon. FRIDAY: Dry and sunny. Freezing level around 1700 m. Winds calm.
Avalanche Summary
A few glide slab avalanches up to size 2.5 have been reported near Terrace since Sunday on southerly slopes. Glide slabs typically happen on steep, smooth terrain features such as rock slabs or grassy slopes with little roughness. They are most common on southerly aspects, but during especially warm weather, may occur on shady aspects as well. Slopes with obvious large cracks (glide cracks) as well as slopes with a known history of glide releases are best avoided.
Snowpack Summary
Dry snow remains on shady slopes in the alpine. In these locations, 50-100 cm of well settled snow overlies a layer of weak facets that were buried around March. 10th. This is currently the primary layer of concern for human triggering persistent slab avalanches, although recent observations suggest it has become difficult to trigger an avalanche on this layer.Not much further below the March 10th interface is a second weak layer of facets buried on February 19th. Recent loose wet and slab avalanches have been observed gouging into this faceted snow and entraining additional mass.The prolonged warm spell has transitioned sun exposed slopes in the alpine and on all aspects at treeline and below towards becoming isothermal (0 C throughout the snowpack). In these areas spring conditions are in effect; the avalanche hazard will fluctuate greatly depending on the strength of the overnight freeze and how quickly the snowpack is warmed up each day. Check out this guide to managing avalanche hazard during spring conditions HERE.
Problems
Loose Wet
When the sun comes out and temperatures rise during the day, loose wet avalanches will be very likely to occur on sun-affected slopes.
Avoid terrain traps such as cliffs and gullies that increase the consequence of small avalanches.Avoid sun exposed slopes when the solar radiation is strong, especially if the snow is moist or wet.Cornices become weak with daytime heating, travel early on exposed slopes.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Wet Slabs
Wet slab avalanches are possible on steep, smooth slopes that face the sun.
Avoid slopes with glide cracks.Avoid slopes with a known history of glide avalanches, such as smooth rocky slopes.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 27th, 2019 2:00PM
