[CB]

Avalanche Bulletin - Glacier National Park

Issued Sat Apr 19, 2014 08:01
Valid Until Sun Apr 20, 2014 08:00
Large areas of Glacier National Park are CLOSED for avalanche control using EXPLOSIVES. Daily or annual winter permits are required to access winter restricted areas. Access information is available at the Rogers Pass Discovery Centre.
If the sun stays out this afternoon and the solar inputs are high, avalanche hazard will rise.  Use caution in these conditions on and below sun effected terrain.

        

Danger Ratings: Saturday

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 Sunday Monday
alpine
3 - Considerable 2 - Moderate
treeline 2 - Moderate 2 - Moderate
below treeline 2 - Moderate 2 - Moderate
Confidence: Fair - Freezing levels are uncertain

Weather Observations

Past 24 Hr WeatherFidelity 1905mRogers Pass 1315m
Maximum (°C)-22
Minimum (°C)-6-2.5
Snowfall (cm)50.1
Snow Pack (cm)355161
Wind speedLight (1-25 km/h)Moderate (26-40 km/h)
Ridgetop wind directionSSW
Past 24 Hr WeatherFidelity 1905mRogers Pass 1315m
Maximum (°C)-22
Minimum (°C)-6-2.5
Snowfall (cm)50.1
Snow Pack (cm)355161
Wind speedLight (1-25 km/h)Moderate (26-40 km/h)
Ridgetop wind directionSSW
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: Wind Slabs

Which Elevation?

Which Elevation? alpine, treeline

Which Slopes?

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

Chance of Avalanches?

Chance of Avalanches? possible

Expected Size?

Expected Size? small - large
New snow and moderate S/SW winds have formed wind slabs in exposed terrain in the last few days. Use caution on these firm pockets of wind deposited snow.

Travel and Terrain Advice

  • Use caution in lee areas. Recent wind loading have created wind slabs.
  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Problem 2: Loose Wet

Which Elevation?

Which Elevation? below treeline, treeline

Which Slopes?

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

Chance of Avalanches?

Chance of Avalanches? possible

Expected Size?

Expected Size? small - large
Moist new snow, mixed with rain, will bond poorly to the weak crust and nearly isothermal snow below. Sunny breaks will weaken the snowpack. Wind loading may trigger avalanches, becoming loose wet.

Travel and Terrain Advice

  • Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Problem 3: Cornices

Which Elevation?

Which Elevation? alpine

Which Slopes?

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

Chance of Avalanches?

Chance of Avalanches? possible - likely

Expected Size?

Expected Size? large - very large
Temperature swings and solar inputs have weakened cornices. If these large triggers fail, they could trigger a big, high consequence avalanche.

Travel and Terrain Advice

  • Cornices become weak with daytime heating, so travel early on exposed slopes.
  • Give cornices a wide berth when travelling on or below ridges.