Avalanche Forecast
Issued: Jan 13th, 2019 4:08PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
ghelgeson,
Avalanche Canada
Storm slabs below treeline are rapidly becoming less of a problem, but little is known about the alpine. If you are increasing your exposure to avalanche terrain, take a cautious approach and do it gradually as you gather information.
Summary
Confidence
Low - Due to the number of field observations
Weather Forecast
After an intense storm cycle we transition into a warm and dry period to kick off the work week. The freezing level should return to valley bottom by Wednesday, but no significant precipitation is expected for the rest of the week.SUNDAY NIGHT: Freezing level around 1500 m, moderate to strong south/southwest wind, 2 to 6 mm of precipitation falling as snow above 1300 m.MONDAY: Broken cloud cover, freezing level around 1600 m, light to moderate southwest wind, trace of snow possible.TUESDAY: Scattered cloud cover, freezing level around 2000 m, light to moderate southerly wind, no significant precipitation expected.WEDNESDAY: Scattered cloud cover, freezing level at valley bottom, light southeast wind, no significant precipitation expected.
Avalanche Summary
On Saturday control work produced storm slabs up to size 2.5. A natural size 2.5 in a steep northeast facing couloir feature around 1700 m was also reported.On Friday steep alpine features in Bear Pass produced natural avalanches from size 2.5 to 3.5, natural avalanches from size 1.5 to 2.5 were reported at and below treeline. In the Skeena corridor loose wet avalanches to size 1.5 were reported at and below treeline. Visibility was limited, but natural avalanches to size 3 were reported from several avalanche paths. Natural avalanche activity likely continued through Saturday.An avalanche incident was reported in the Shames backcountry area on Thursday. The incident involved two skier triggered avalanches occurring in succession with two people involved and partially buried. The details can be found on the Mountain Information Network. (here)
Snowpack Summary
The Northwest Coast has seen upwards of 100 mm of precipitation since Wednesday. Above 1500 m most of the precipitation came in as snow, slopes below 1500 m were largely rain soaked, particularly in southern portions of the region around Terrace. Strong to extreme wind and mild temperatures associated with the warm storm have formed widespread storm slabs. In some sheltered areas the new snow is sitting on a weak layer of surface hoar (feathery crystals). For most of the region, a weak layer of facets (sugary snow) buried in early December exists down 180-250 cm. The likelihood of triggering this layer is decreasing, but it could be triggered by humans in shallow snowpack areas. The potential may also exist for storm slab avalanches to step down to this layer, resulting in large avalanches.In the northern part of the region, near Ningunsaw pass, a couple of weak layers of surface hoar may be found down approximately 150 to 220 cm.
Problems
Storm Slabs
Storm slabs likely remain sensitive to human triggering. We have very few observations from the alpine, but it's suspected that storm slabs are deep and capable of producing very large avalanches at upper elevations.
If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Continue to make conservative terrain choices while the storm snow settles and stabilizes.Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 14th, 2019 2:00PM
