Avalanche control continues to produce spectacular results in alpine terrain.
Continue to use caution as you approach, or are exposed to, higher terrain. This is where the persistent slab has been the most reactive and where the winds have developed slab properties in the mid and upper snowpack.
Continued inputs of snow combined with moderate to strong south to west winds have created fresh wind slabs in the alpine and in open terrain at treeline. Slab development will continue through Wednesday as this pattern of incremental loading persists.
The natural avalanche cycle on the mid-November persistent layers down 80-140 cm has ended; however, explosive control results highlight the potential for human triggering remains. The snowpack needs time to adjust to the recent large load.
The ski hills produced mainly windslabs in previously worked terrain: 20-30cm deep up to sz 2 (some running far at Lake Louise). SSV produced a few slabs up to sz 2.5 on the ground in windward, previously shallow, terrain.
Control work on Hwy 93N mainly gave slabs on the ground and others on the persistent slab up to sz 3. But: the Hector path went sz 4. The initial slab continued to pull sidewalls through the upper track, depositing a pile 4 m deep, 30 m wide, and 50m long on the road.
10-20cm of snow over the last 48 hours brings the total snow depth over the December 15 melt-freeze crust (below ~2000m) up to 35-60cm. Moderate to strong S-W winds continue to develop slabs in the alpine and at treeline.
The mid-November facet/crust layers are down 80-140 cm and remain active this week with numerous large natural and explosive controlled avalanches.
Treeline snow depths are between100-180 cm.
The low on BC coast will spin a few pulses to the region with a SW flow as the cold air holds over the prairies.
A brisk cold front will bring a few cm of snow early Tuesday with winds increasing to the moderate to strong range in the alpine. Temperatures at treeline steady near -10C. Winds back off a bit through the day as skies clear.
Another system Wednesday.
Link to updated weather forecast tables from Environment Canada
