[LP]

Avalanche Bulletin - Banff, Yoho and Kootenay National Parks

Issued Fri Apr 18, 2014 17:00
Valid Until Sat Apr 19, 2014 17:00
Freezing levels could climb to as high as 2500 m over the weekend. Watch for increased loose snow avalanches with wind gusts and solar affect.
Get a very early start - Best skiing will be above treeline on North aspects.

        

Danger Ratings: Saturday

alpine treeline below treeline alpine: 2 - Moderate, treeline: 1 - Low, below treeline: 2 - Moderate
alpine: 2 - Moderate
2 - Moderate Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
  • Natural avalanches unlikely; human-triggered avalanches possible.
  • Small avalanches in specific areas; or large avalanches in isolated areas.
More...
treeline: 1 - Low
1 - Low Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
  • Natural and human-triggered avalanches unlikely.
  • Small avalanches in isolated areas or extreme terrain.
More...
below treeline: 2 - Moderate
2 - Moderate Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
  • Natural avalanches unlikely; human-triggered avalanches possible.
  • Small avalanches in specific areas; or large avalanches in isolated areas.
More...
Forecast Sunday Monday
alpine
2 - Moderate 2 - Moderate
treeline 1 - Low 1 - Low
below treeline 2 - Moderate 2 - Moderate

Weather Observations

Past 24 Hr WeatherN Kootenay 1985/2405mBow Summit 2000mSunshine 2200m
Maximum (°C)Not Available00
Minimum (°C)-4-7-7
Snowfall (cm)20156
Snow Pack (cm)235167192
Wind speedLight (1-25 km/h)Light (1-25 km/h)Moderate (26-40 km/h)
Ridgetop wind directionSWNot AvailableSW
Past 24 Hr WeatherN Kootenay 1985/2405mBow Summit 2000mSunshine 2200m
Maximum (°C)Not Available00
Minimum (°C)-4-7-7
Snowfall (cm)20156
Snow Pack (cm)235167192
Wind speedLight (1-25 km/h)Light (1-25 km/h)Moderate (26-40 km/h)
Ridgetop wind directionSWNot AvailableSW
Low Moderate Considerable High Extreme
  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
  • Natural and human-triggered avalanches unlikely.
  • Small avalanches in isolated areas or extreme terrain.
  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
  • Natural avalanches unlikely; human-triggered avalanches possible.
  • Small avalanches in specific areas; or large avalanches in isolated areas.
  • Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
  • Natural avalanches possible; human-triggered avalanches likely.
  • Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.
  • Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
  • Natural avalanches likely; human-triggered avalanches very likely.
  • Large avalanches in many areas; or very large avalanches in specific areas.
  • Avoid all avalanche terrain.
  • Natural and human-triggered avalanches certain.
  • Large to very large avalanches in many areas.

Problem 1: Deep Persistent Slabs

Which Elevation?

Which Elevation? alpine

Which Slopes?

Which Slopes? south, southeast, east, northeast, north, northwest, west, southwest

Chance of Avalanches?

Chance of Avalanches? unlikely - possible

Expected Size?

Expected Size? small - large
The basal layer is still prominent in thin and variable areas.  It is well bridged and is unlikely to be triggered, but consequences could be large if you hit the right spot.  With warmer temps & sun affect it may become more sensitive to triggering.

Travel and Terrain Advice

  • Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Problem 2: Loose Dry

Which Elevation?

Which Elevation? alpine

Which Slopes?

Which Slopes? north, northeast, east, southeast, south, southwest, west, northwest

Chance of Avalanches?

Chance of Avalanches? possible

Expected Size?

Expected Size? small - small
Watch for an increase loose dry avalanches off cliffs with forecasted gusty winds and solar affect.

Travel and Terrain Advice

  • Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

Problem 3: Loose Wet

Which Elevation?

Which Elevation? below treeline, treeline

Which Slopes?

Which Slopes? west, southwest, south, southeast

Chance of Avalanches?

Chance of Avalanches? possible

Expected Size?

Expected Size? small - large
Watch for loose wet avalanches being triggered by sun affect, potentially initiating from cliffs/rocks above, entraining the recent storm snow, and sliding on underlying crusts.

Travel and Terrain Advice

  • Start and finish early before the surface crusts melt.