Late season powder
A recent late season dump gives one last taste of winter as things get deep again.
South Coast Avalanche Forecast
Date/Time issued:
Friday, March 28, 2008 at 4:00 PM
Valid until:
Monday, March 31, 2008 at 6:00 PM
Next Scheduled Update:
Monday, March 31, 2008
---------- Sea-to-Sky ----------
Saturday Sunday Monday
Alpine 3 - CONSIDERABLE 2 - MODERATE 2 - MODERATE
Treeline 2 - MODERATE 2 - MODERATE 2 - MODERATE
Below Treeline 1 - LOW 1 - LOW 1 - LOW
---------- Duffy Lake & Inland Areas ----------
Saturday Sunday Monday
Alpine 3 - CONSIDERABLE 3 - CONSIDERABLE 3 - CONSIDERABLE
Treeline 3 - CONSIDERABLE 2 - MODERATE 2 - MODERATE
Below Treeline 2 - MODERATE 1 - LOW 1 - LOW
Confidence:
Primary Concerns:
Persistent Slab:
40-80cm of storm snow is now sitting on a crust and surface hoar layer from March 10/11 or on sun crusts on south aspects. Wherever this storm snow has formed into a slab, from wind or temperatures, there are human triggered avalanches occurring. This is a particular concern in the Duffy Lake and Inland Areas.
Solar Radiation:
Every day as the south aspects get soft and moist the avalanche danger is rising in response. What is rated as Moderate or Low for the morning freezing temperatures will climb to Considerable or High with the intensity of the sun. My concern is for south facing bowls and large drooping cornices.
--------------------------------------------------------------------------------
Travel Advisory
The valleys are certainly starting to feel like spring, still chilly though. In the mountains it is still very much winter. Given the variety of tricky weak layers with deep wind slabs scattered around the region it will be wise to use caution in any steep, convex or complicated terrain. As the wind and time work the storm snow into more of a slab it will become more important to choose conservative terrain. Even at tree line choosing terrain that is well supported, avoids terrain traps and is lower angle will help reduce your exposure.
Avalanche Activity
The tricky nature of the existing weak layer on the Coast was clear from an incident yesterday north of the Duffy area where a skier was caught and partially buried after triggering a slab on the March 10/11 crust. Numerous loose natural and human triggered sloughs off north aspects will continue through the weekend. Cornices are also continuing to drop off.
Snowpack
40-60cm of storm snow is making for thigh deep foot penetration. The wind is starting to form this up into a soft slab. There are moderate and sudden planar shears being reported down 40-50cm on the March 10/11 layer. South aspects are moist in the mid day and forming into a crust as the diurnal cycle continues. Below the upper snow pack is a very firm and dense mid and lower snow pack which will continue to provide fast traveling for the as long as the weather continues to be cool.
The weather is forecast to bring 5-10cm of snow to the alpine by Saturday night. With convective cells imbedded some valleys may get more intense short bursts of snow fall. Clouds and light flurries are expected for Sunday. The winds will be in the moderate 30km/hr range from the East and swing through the south and west by Sunday. The temperatures will remain cool through the weekend with freezing levels not getting above 800 metres. Monday will bring somewhat clearer conditions.
South Coast Avalanche Forecast
Date/Time issued:
Friday, March 28, 2008 at 4:00 PM
Valid until:
Monday, March 31, 2008 at 6:00 PM
Next Scheduled Update:
Monday, March 31, 2008
---------- Sea-to-Sky ----------
Saturday Sunday Monday
Alpine 3 - CONSIDERABLE 2 - MODERATE 2 - MODERATE
Treeline 2 - MODERATE 2 - MODERATE 2 - MODERATE
Below Treeline 1 - LOW 1 - LOW 1 - LOW
---------- Duffy Lake & Inland Areas ----------
Saturday Sunday Monday
Alpine 3 - CONSIDERABLE 3 - CONSIDERABLE 3 - CONSIDERABLE
Treeline 3 - CONSIDERABLE 2 - MODERATE 2 - MODERATE
Below Treeline 2 - MODERATE 1 - LOW 1 - LOW
Confidence:
Primary Concerns:
Persistent Slab:
40-80cm of storm snow is now sitting on a crust and surface hoar layer from March 10/11 or on sun crusts on south aspects. Wherever this storm snow has formed into a slab, from wind or temperatures, there are human triggered avalanches occurring. This is a particular concern in the Duffy Lake and Inland Areas.
Solar Radiation:
Every day as the south aspects get soft and moist the avalanche danger is rising in response. What is rated as Moderate or Low for the morning freezing temperatures will climb to Considerable or High with the intensity of the sun. My concern is for south facing bowls and large drooping cornices.
--------------------------------------------------------------------------------
Travel Advisory
The valleys are certainly starting to feel like spring, still chilly though. In the mountains it is still very much winter. Given the variety of tricky weak layers with deep wind slabs scattered around the region it will be wise to use caution in any steep, convex or complicated terrain. As the wind and time work the storm snow into more of a slab it will become more important to choose conservative terrain. Even at tree line choosing terrain that is well supported, avoids terrain traps and is lower angle will help reduce your exposure.
Avalanche Activity
The tricky nature of the existing weak layer on the Coast was clear from an incident yesterday north of the Duffy area where a skier was caught and partially buried after triggering a slab on the March 10/11 crust. Numerous loose natural and human triggered sloughs off north aspects will continue through the weekend. Cornices are also continuing to drop off.
Snowpack
40-60cm of storm snow is making for thigh deep foot penetration. The wind is starting to form this up into a soft slab. There are moderate and sudden planar shears being reported down 40-50cm on the March 10/11 layer. South aspects are moist in the mid day and forming into a crust as the diurnal cycle continues. Below the upper snow pack is a very firm and dense mid and lower snow pack which will continue to provide fast traveling for the as long as the weather continues to be cool.
The weather is forecast to bring 5-10cm of snow to the alpine by Saturday night. With convective cells imbedded some valleys may get more intense short bursts of snow fall. Clouds and light flurries are expected for Sunday. The winds will be in the moderate 30km/hr range from the East and swing through the south and west by Sunday. The temperatures will remain cool through the weekend with freezing levels not getting above 800 metres. Monday will bring somewhat clearer conditions.
