Archived

Avalanche Forecast

Apr 24th, 2017–Apr 25th, 2017

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

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: Glacier.

With weak overnight crust recoveries the snowpack is on a tipping point. Without solar, danger will be lower than forecast. However, strong solar is expected later this afternoon and danger will increase to Considerable quickly when the sun comes out

Weather Forecast

Today and tomorrow expect a mix of sun and cloud, with light winds and freezing levels to 1800m. Strong solar is expected in the afternoons. Overnight temps should fall to -6 and with radiant cooling expect a decent overnight recovery. On Wed, we'll see another system arrive bringing 10cm with freezing levels to 1800m. Precip will continue on Thurs

Snowpack Summary

Above ~2300m on N'ly aspects it'll feel like winter, with winter problems. On all other aspects solar and warm temps have resulted in moist snow, and the upper snowpack consists of a series of crusts. Below treeline the snowpack is becoming isothermal. We have yet to see a proper melt-freeze cycle, the surface crusts are weak and break down quickly

Avalanche Summary

On high elevation N'ly aspects (where the skiing is still good) skiers have been triggering soft slabs. Yesterday skiers triggered a size 2 windslab in Cheops N5, a N aspect @2250m. It was 20cm deep but ran 300m. Shooting cracks also had a group turn around on Ursus Major. Loose wet avalanches continue to occur daily up to size 3, running onto fans

Confidence

Timing or intensity of solar radiation is uncertain

Avalanche Problems

Wind Slabs

On high elevation N'ly aspects, where dry snow and good skiing still exists, watch for windslabs. Yesterday skiers reported triggering windslabs on lee features. One was a size 2 that ran 300m.

Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 3

Loose Wet

Warm overnight temps have been preventing a melt-freeze cycle. Surface crusts break down quickly during the day, especially when the sun comes out. Avalanches that start high pick up mass down low where the snowpack is weak and isothermal.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Use extra caution on slopes if the snow is moist or wet.

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

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Cornices

Huge cornices loom over many slopes. Strong solar is expected late in the day and may weaken these monsters causing them to fail. Cornices are the most likely trigger for deep persistent slabs, resulting in very large avalanches.

Cornices become weak with daytime heating, so travel early on exposed slopes.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 2 - 3