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Avalanche Bulletin - Waterton Lakes National Park

Issued Sun Apr 27, 2014 17:00
Valid Until further notice
Public Bulletins will no longer be provided for the 2013/14 season however avalanche hazard will persist later this year with an above average snowpack. Contact Visitor Safety at WLNP for help with safe trip planning in the spring and summer seasons.

        

Danger Ratings: Monday

alpine treeline below treeline alpine: N/A - No Rating, treeline: N/A - No Rating, below treeline: N/A - No Rating
alpine: N/A - No Rating
N/A - No Rating N/A
N/A
treeline: N/A - No Rating
N/A - No Rating N/A
N/A
below treeline: N/A - No Rating
N/A - No Rating N/A
N/A
Forecast Tuesday Wednesday
alpine
N/A - No Rating N/A - No Rating
treeline N/A - No Rating N/A - No Rating
below treeline N/A - No Rating N/A - No Rating

Weather Observations

Past 24 Hr WeatherLittle Prairie 1650m
Maximum (°C)7
Minimum (°C)-3
Snowfall (cm)13
Snow Pack (cm)164
Wind speedLight (1-25 km/h)
Ridgetop wind directionNE
Past 24 Hr WeatherLittle Prairie 1650m
Maximum (°C)7
Minimum (°C)-3
Snowfall (cm)13
Snow Pack (cm)164
Wind speedLight (1-25 km/h)
Ridgetop wind directionNE
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? southwest, south, southeast, west, northwest, north, northeast, east

Chance of Avalanches?

Chance of Avalanches? likely

Expected Size?

Expected Size? small - large
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.

Travel and Terrain Advice

  • Travel early on frozen crusts before the heat of the day.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Problem 2: Storm Slabs

Which Elevation?

Which Elevation? below treeline, alpine, treeline

Which Slopes?

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

Chance of Avalanches?

Chance of Avalanches? possible - likely

Expected Size?

Expected Size? small - large
As spring storms continue to bring additional snow watch for new storm and windslabs to form over surface crusts

Travel and Terrain Advice

  • Avoid freshly wind loaded features.
  • The new snow will requires several days to settle and stabilize.

Problem 3: Deep Persistent Slabs

Which Elevation?

Which Elevation? alpine, treeline, below treeline

Which Slopes?

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

Chance of Avalanches?

Chance of Avalanches? unlikely - possible

Expected Size?

Expected Size? large - very large
Sustained heating will weaken the upper snowpack as the days become warmer and the weak basal layers are likely to allow for some large avalanches. Remember cornice failures and smaller avalanches hitting a slope could trigger these serious slabs.

Travel and Terrain Advice

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