February 4, 2002

Canadian Avalanche Association Bulletin

SOUTH COLUMBIA REGION

WEATHER: The South Columbias experienced generally favourable weather for
the weekend, with light amounts of snow and generally warm conditions. The
weather forecast calls for a ridge of high pressure to dominate for the
week, with clear nights and dry conditions. A temperature inversion may
develop, with cool air pooling in valleys, and warmer air trapped above.
Some low elevation fog may result.
SNOWPACK: A series of weak systems left behind about 30 cm of storm snow,
with an easy shear present mid way in the new snow. This had improved
rapidly by Monday. A buried surface hoar layer, often associated with a
crust just below, is still showing up as a significant weakness in some
areas, but completely absent in others. Shallow snowpack areas are still
plagued by the November crust still preserved in the lower snowpack.
AVALANCHES: Widespread but small natural activity occurred on the weekend in
the storm snow. This often stepped down to the January 2nd layer now down
about 60cm. Two human triggered avalanches in the Purcells stepped down to
the November Crust to produce avalanches up to 3.5 in size. Remote
triggering, where a settlement was felt and an avalanche was triggered some
distance away, was also commonly reported.
FORECAST OF AVALANCHE DANGER UP TO THURSDAY EVENING (Feb 7th)
ALPINE - Considerable
TREELINE - Considerable
BELOW TREELINE - Moderate
TRAVEL ADVISORY: In shallow areas, keep these releases on the November Crust
in mind. Not many survive being in an avalanche size 3 or larger. Human
triggering on the January 2nd buried surface hoar layer seems to be
associated with subtle terrain changes, such as small convex rolls that are
slightly steeper than the overall slope. With the proper choice of terrain
this week should be a very good time to be in the mountains.