Avalanche Forecast

Issued: Apr 3rd, 2014 4:00PM

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

tim haggarty, Parks Canada

Waterton Lakes.

Watch for even short periods of solar heating or rain to cause an increase in hazard beyond the posted Danger Ratings.

Summary

Weather Forecast

Up to 5cm Friday and 5 Saturday is forecast to arrive with continued moderate West winds. Strong solar heating Thursday with a poor recovery expected overnight. Freezing levels quickly returning to 1800m Friday then 1600m for Saturday and 1800m again for Sunday. A freezing level of 3000m with sunny periods will be a significant change for Monday.

Snowpack Summary

Surface crusts on East through West aspects have formed with the daily heating pattern. A shear persists down about 30 cm on shaded aspects on the 0325 interface. March crusts down 70 to 100cm on all but North aspects above treeline could be a problem with strong sustained warming or rain. Feb facets still a concern in high elevation thin areas.

Avalanche Summary

Only superficial loose moist activity has been seen over the last few days however a few significant slabs were triggered by cornice failures associated with wind and warming last weekend.

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Storm Slabs

Skiers looking for dry snow on 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. Intense periods of radiation will trigger avalanches or cause cornice failures that could trigger avalanches as well.

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

Although unlikely, a large load such as a cornice failure or another avalanche could trigger all of the snow above these strong crusts. Significant and sustained heating or rain may also allow these slabs to become active such as is forecast Monday.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Apr 6th, 2014 4:00PM