Avalanche Forecast

Issued: Apr 14th, 2014 7:36PM

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

Tim Haggarty, Parks Canada

Waterton Lakes.

Watch incoming snow amounts carefully: new snow will likely bond poorly to the extensive crusts. Remember, small amounts of solar heating or rain can weaken snow quickly to cause an increase in the avalanche hazard beyond the posted danger ratings.

Summary

Weather Forecast

Tuesday will bring light precip with a freezing level of 1900m and light to moderate West winds. Winds will shift N Wed with freezing levels dropping to 1500m and continued light precip - 10cm. Thursday should bring lighter precip and W winds however freezing will return to 1800m.

Snowpack Summary

Strong heating has built crusts on all aspects to 2300m and to ridgelines on solar aspects. Isolated windslabs exist in open features treeline and above. The upper and mid snowpack is now quite strong however the deeply buried February Facets and early season Basal Facets remain weak. Cornices appear to be large and fragileÂ and deserve respect.

Avalanche Summary

Daily loose moist activity on all aspects below treeline and to mountain tops on sun exposed aspects has been seen over the last few days. This activity has been mainly minor with good freezes and well established surface crusts however size 2 avalanches have been recorded and are a reminder that strong solar heating can break down the crusts.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Loose Wet

Even short bursts of solar heating can rapidly affect the snow this time of the year. With mild temperatures in the forecast, watch for rain to affect the snow at lower elevations.

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

Possible - Likely

Expected Size

1 - 2

Wind Slabs

Isolated and thin windslabs have been built in open features and can be found poorly bonded to crusts. Watch for these to grow or to become hidden with incoming snow.

Be cautious as you transition into wind affected terrain.The recent snow may now be hiding windslabs that were easily visible before the snow fell.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

Weak snow deep in the snowpack should be kept on the radar for those traveling to more exposed places. A large load such as a cornice fall or significant and sustained heating may wake this problem up in many locations in the near future.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.Pay attention to overhead hazards like cornices.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Apr 17th, 2014 4:00PM