Avalanche Forecast

Issued: Apr 5th, 2014 11:43AM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Storm Slabs, Loose Wet and Persistent Slabs.

Tim Haggarty, Parks Canada

Waterton Lakes.

Even short periods of solar heating or rain may cause an increase in the hazard beyond the posted Danger Ratings. Be conservative Monday and Tuesday as the snowpack will be stressed by the highest freezing levels encountered yet this season.

Summary

Weather Forecast

Convective flurries combined with moderate West winds will allow for both snow and sunshine this weekend. With freezing levels around 15-1800m watch for rain at low elevations and solar heating to quickly affect surface snow. Monday freezing levels willÂ rise to 2700m. With a poor recovery and more heating into Tuesday the snowpack will be weakened

Snowpack Summary

Surface crusts on East through West aspects have formed with the daily heating pattern and rain below 1700m. Down 30 to 40cm on shaded aspects a shear persists on the 0325 interface.Â The strong March crusts are found down 70 to 100cm on all but North aspects above treeline and overlieÂ the Feb facets that remain weak at about 1m above the ground.

Avalanche Summary

Superficial loose moist activity has been seen over the last few days as a result of heating. In the last week a few significant slabs were triggered by cornice failures associated with wind and warm conditions. Expect this activity to increase as we move into warmer days.

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Storm Slabs

Skiers looking for dry snow on the shaded aspects should frequently test the surface layers. A shear persists down about 30 cm with preserved stellar snow flakes and surface hoar. Caution in steep and unsupported terrain is advised.

Be cautious as you transition into wind affected terrain.Dig down to find and test weak layers before committing to a line.

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

Daily heating and the sun will create moist snow at low elevations and on solar aspects. As crusts break down avalanches will result. Cornices will also be affected by this heating and could trigger persistent slabs.

Avoid avalanche terrain during periods of rain.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Persistent Slabs

With significant heating in the forecast for Monday and Tuesday deep slabs may become active. Large loads such as falling cornices or smaller avalanches could trigger large avalanches on the March crusts or even the February facets.

Be increasingly cautious on sun exposed slopes.Pay attention to overhead hazards like cornices.

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

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Apr 8th, 2014 4:00PM