[BW]

Avalanche Bulletin - Banff, Yoho and Kootenay National Parks

Issued Tue Apr 22, 2014 17:30
Valid Until Wed Apr 23, 2014 17:00
Spring time conditions exist. Pay attention to how strong the overnight freeze is and how quickly it warms during the day. Start your tours early and be home before it warms up.

        

Danger Ratings: Wednesday

alpine treeline below treeline alpine: 2 - Moderate, treeline: 3 - Considerable, below treeline: 3 - Considerable
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: 3 - Considerable
3 - Considerable Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
  • 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.
More...
below treeline: 3 - Considerable
3 - Considerable Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
  • 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.
More...
Forecast Thursday Friday
alpine
3 - Considerable 3 - Considerable
treeline 3 - Considerable 3 - Considerable
below treeline 3 - Considerable 3 - Considerable
Confidence: Fair - Freezing levels are uncertain on Wednesday

Weather Observations

Past 24 Hr WeatherN Kootenay 1985/2405mBow Summit 2000mSunshine 2200m
Maximum (°C)7Not Available4
Minimum (°C)-2Not Available-4
Snowfall (cm)0Not Available0
Snow Pack (cm)234Not Available182
Wind speedLight (1-25 km/h)Not AvailableLight (1-25 km/h)
Ridgetop wind directionSNot AvailableSE
Past 24 Hr WeatherN Kootenay 1985/2405mBow Summit 2000mSunshine 2200m
Maximum (°C)7Not Available4
Minimum (°C)-2Not Available-4
Snowfall (cm)0Not Available0
Snow Pack (cm)234Not Available182
Wind speedLight (1-25 km/h)Not AvailableLight (1-25 km/h)
Ridgetop wind directionSNot AvailableSE
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: Loose Wet

Which Elevation?

Which Elevation? below treeline, treeline, alpine

Which Slopes?

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

Chance of Avalanches?

Chance of Avalanches? possible - likely

Expected Size?

Expected Size? small - large
Loose wet avalanches are possible in the afternoon as a result of day time heating. Monitor how thick the crusts are and how quickly they break down during the day.

Travel and Terrain Advice

  • Avoid avalanche terrain during periods of rain.

Problem 2: Deep Persistent Slabs

Which Elevation?

Which Elevation? alpine, treeline

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
Although unlikely it is still possible to trigger a slab avalanche on  one of the deep persistent layers. Skier triggering of this layer is more likely in shallow snowpack areas.

Travel and Terrain Advice

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

Problem 3: Cornices

Which Elevation?

Which Elevation? alpine

Which Slopes?

Which Slopes? north, northeast, east, southeast, northwest

Chance of Avalanches?

Chance of Avalanches? possible - likely

Expected Size?

Expected Size? small - large
Cornices weaken with day time heating. Field observations show numerous recent cornice collapses.

Travel and Terrain Advice

  • Do not travel on slopes that are exposed to cornices overhead.