Large destructive avalanches in this region highlight the importance of sticking to simple low-angled terrain and avoiding overhead hazards like cornices.
Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
WEDNESDAY: Mix of sun and cloud / light to moderate west wind / alpine temperatures around -11 C.THURSDAY: Mix of sun and cloud / moderate west wind / alpine temperatures around -9 C.FRIDAY: Isolated flurries / moderate to strong west wind / alpine temperatures around -7 C.
Avalanche Summary
On Tuesday, a few natural wind slabs (size 2) were reported in the southeast part of the region. A few large deep persistent slab avalanches (up to size 3) have been reported over the past few days, many of which were triggered by cornices on north and east facing slopes. On Sunday, a size 2 deep persistent slab avalanche was triggered by a snowcat on a southeast aspect at 1900m. This avalanche was 180 cm deep and ran on facets sitting on a rain crust buried at the end of November. The snowpack in the region remains suspect with several buried weak layers displaying classic signs of instability such as whumpfing and cracking. The recent video posted to the Avalanche Canada South Rockies field team Facebook page paints a pretty clear picture.
https://www.facebook.com/avcansouthrockies/videos/1894352117306941/.
Snowpack Summary
15 cm of fresh snow and strong winds have formed wind slabs in exposed terrain and fragile cornices along ridgetops. Warm temperatures on Monday left moist snow and crusts up to about 1700 m.About 20-50 cm of recent snow covers a layer of feathery surface hoar in sheltered areas and a sun crust on solar aspects that was buried in mid-January. About 30-60 cm below the surfaces lies the early-January surface hoar layer. About 60-80 cm below the surface a weak layer of feathery surface hoar crystals and/or sun crust buried in mid-December is found at treeline and below treeline elevations. A weak layer of rain crusts and sugary facets buried in late-November exists near the base of the snowpack. Although the snowpack structure is variable across the region, these persistent weak layers are generally widespread. Snowpack depths are also variable across the region and typically thinner in northern areas than in areas to the south.
shorton,
Avalanche Canada
