[GL]

Avalanche Bulletin - Jasper National Park

Issued Wed Apr 23, 2014 17:30
Valid Until Thu Apr 24, 2014 17:00
Assess the new storm snow's bonding to the crust below. Will take few days to bond. Spring conditions exist so start early and end early.

        

Danger Ratings: Thursday

alpine treeline below treeline alpine: 2 - Moderate, treeline: 2 - Moderate, 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: 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...
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 Friday Saturday
alpine
1 - Low 1 - Low
treeline 2 - Moderate 1 - Low
below treeline 2 - Moderate 2 - Moderate
Confidence: Good - The weather pattern is stable

Weather Observations

Past 24 Hr WeatherMarmot Basin 0800Columbia Icefields area
Maximum (°C)34
Minimum (°C)-5-5
Snowfall (cm)33
Snow Pack (cm)136Not Available
Wind speedLight (1-25 km/h)Light (1-25 km/h)
Ridgetop wind directionSENW
Past 24 Hr WeatherMarmot Basin 0800Columbia Icefields area
Maximum (°C)34
Minimum (°C)-5-5
Snowfall (cm)33
Snow Pack (cm)136Not Available
Wind speedLight (1-25 km/h)Light (1-25 km/h)
Ridgetop wind directionSENW
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: Storm Slabs

Which Elevation?

Which Elevation? alpine, treeline

Which Slopes?

Which Slopes? southeast, south, southwest, west, east

Chance of Avalanches?

Chance of Avalanches? possible

Expected Size?

Expected Size? small - large
Tuesday's storm did not bring a lot of snow yet it was enough to form a thin storm slab. It rests on slippery temperature crust and may have more depth to it where wind loading has occurred. It will meld into the snowpack but give it a few days.

Travel and Terrain Advice

  • The new snow will require several days to settle and stabilize.

Problem 2: Loose Wet

Which Elevation?

Which Elevation? below treeline, treeline, alpine

Which Slopes?

Which Slopes? southeast, south, southwest, west

Chance of Avalanches?

Chance of Avalanches? possible

Expected Size?

Expected Size? small - large
Cooler temperatures are regulating loose wet avalanches; however, when the sun pokes out, solar aspects can quickly wake up increasing the overall danger. Depending on the overnight freeze, lower elevations will tend to wake up quicker.

Travel and Terrain Advice

  • Make your travel plans to take advantage of overnight freezing.
  • Start and finish early before the surface crusts melt.

Problem 3: Deep Persistent Slabs

Which Elevation?

Which Elevation? alpine, treeline

Which Slopes?

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

Chance of Avalanches?

Chance of Avalanches? unlikely - possible

Expected Size?

Expected Size? small - large
Large triggers such as cornice failures have the potential to initiate deep avalanches. Depending on aspect, could be a wet or dry slab. Consequences would be severe. Be aware of shallow spots as trigger zones and looming cornices about to drop.

Travel and Terrain Advice

  • Minimize overhead exposure during periods of heavy loading from new snow, wind.
  • Be aware of thin areas that may propogate to deeper instabilites.