January 31, 2008
Whistler Avalanche conditions
January 31, 2008
Alpine: Considerable
Treeline: Moderate
Below Treeline: Moderate
Travel Advisory: A total of 43 cm of cold low density snow has fallen since Saturday, 15cm of which arrived during the past 24hrs. Strong South-Easterly winds accompanied last night’s snowfall. The low density surface layers of snow have been readily transported by the wind resulting in soft slab formation to the lee of ridge-tops and any terrain features in the high alpine up to 75cm in depth. In some areas the wind pressed surfaces from last week’s outflow winds are still very much in evidence. Keep in mind that large unpredictable avalanches are still very much a possibility, particularly if a cornice fall is involved.
Avalanche Activity: Explosive and ski testing carried out this morning resulted in widespread soft slab avalanche activity predominantly up to size 1.5 within the most recent storm snow layers. One non-ski compacted start zone ran to size two with the most recent windslab stepping down deeper to last weeks wind-hammered surface. The most recent activity on the Dec 04 Crust and facet layer was on January 21st and was initiated by a large cornice fall. New cornice tabs are soft and have been observed to be very fragile.
Snowpack: The snow that has fallen since last Saturday is overlying a variety of old hard surfaces that were created by last week’s strong NE winds and sun. Surface hoar up to 10mm in size formed last week at treeline and below on top of a layer of faceted snow. These layers are now buried by up to 45cm of loose and unconsolidated storm snow, and up to 75cm deep in the Powder Mtn region. In some locations in the vicinity of any creek beds these crystals are much larger and could provide a failure plane for future avalanche activity with additional loading. The December 4th raincrust and facet crystal weakness is well buried in most areas, and although it has gradually been gaining strength, it has continued to pop up sporadically. Its unpredictable and persistent nature has been problematic and backcountry travelers should continue to be cautious. The deep slab releases have generally appeared to initially fail in a shallow part of the slab in rocky start zones, propagating into the deeper areas.
Weather: Snow flurries today will taper off overnight, with a mix of cloud, sun and scattered flurries for tomorrow. The next organized system is expected to arrive onshore late in the day on Saturday, but the main energy of that system appears to be heading to the south of our region.
January 31, 2008
Alpine: Considerable
Treeline: Moderate
Below Treeline: Moderate
Travel Advisory: A total of 43 cm of cold low density snow has fallen since Saturday, 15cm of which arrived during the past 24hrs. Strong South-Easterly winds accompanied last night’s snowfall. The low density surface layers of snow have been readily transported by the wind resulting in soft slab formation to the lee of ridge-tops and any terrain features in the high alpine up to 75cm in depth. In some areas the wind pressed surfaces from last week’s outflow winds are still very much in evidence. Keep in mind that large unpredictable avalanches are still very much a possibility, particularly if a cornice fall is involved.
Avalanche Activity: Explosive and ski testing carried out this morning resulted in widespread soft slab avalanche activity predominantly up to size 1.5 within the most recent storm snow layers. One non-ski compacted start zone ran to size two with the most recent windslab stepping down deeper to last weeks wind-hammered surface. The most recent activity on the Dec 04 Crust and facet layer was on January 21st and was initiated by a large cornice fall. New cornice tabs are soft and have been observed to be very fragile.
Snowpack: The snow that has fallen since last Saturday is overlying a variety of old hard surfaces that were created by last week’s strong NE winds and sun. Surface hoar up to 10mm in size formed last week at treeline and below on top of a layer of faceted snow. These layers are now buried by up to 45cm of loose and unconsolidated storm snow, and up to 75cm deep in the Powder Mtn region. In some locations in the vicinity of any creek beds these crystals are much larger and could provide a failure plane for future avalanche activity with additional loading. The December 4th raincrust and facet crystal weakness is well buried in most areas, and although it has gradually been gaining strength, it has continued to pop up sporadically. Its unpredictable and persistent nature has been problematic and backcountry travelers should continue to be cautious. The deep slab releases have generally appeared to initially fail in a shallow part of the slab in rocky start zones, propagating into the deeper areas.
Weather: Snow flurries today will taper off overnight, with a mix of cloud, sun and scattered flurries for tomorrow. The next organized system is expected to arrive onshore late in the day on Saturday, but the main energy of that system appears to be heading to the south of our region.
