South Rockies

Poor - Due to limited field observations

Tuesday brought the clouds down to the valley floor as a quick hitting cold front passed over the region. High pressure builds back into the area Wednesday and then the ridge dominates the weather pattern through the end of the work week. Winds will be at light to moderate speeds out of the W/NW all day Wednesday. Freezing levels creep up to 800m Wednesday before dropping back to the valley floor overnight. Temps are cool; I'm expecting daytime highs near -9 at treeline Wednesday with overnight low's dipping down to -12 in the wake of the cold front.

We have a report of a large avalanche (size 3.0) triggered by a snowmobiler in the Mt. Corbin area on Saturday. Sounds like some snow stiffened by the wind released down deep on the weak facets. We will try to get more information up soon. Check-out the CAC Field Team`s observations from last week in our South Rockies discussion forum.If you have any observations from the field, please drop us an email: [email protected].

Snowfall accumulations have not been sufficient to create an avalanche problem below treeline where the snowpack sits at about 30-60cms. Regardless, slopes at higher elevations have produced avalanches large enough to run down to terrain located well below treeline. In the alpine, and at treeline the snowpack depth generally sits anywhere from 80-120cm with deposits of up to 400 cm on wind-loaded features.Reports suggest that strong to extreme winds in a few parts of the region have stripped west aspects of snow creating wind slabs on lee and cross-loaded aspects in the alpine and at treeline. Many of these new windslabs could be sitting on the reactive October rain crust located a few cms above the ground. This rain crust may have weak, overlying facets and is widespread in the alpine and isolated in its distribution at treeline. This is a classic low probability-high consequence scenario where the snow may have been gaining strength, but the consequence of a full-depth avalanche could be disastrous. It's worth noting that while the crust-facet combo has been an issue in some areas, it seems to be non-existent in others parts of the region. The 'take home' message is that the region as a whole is data-sparse and extremely variable in terms of snowpack structure. When heading into avalanche terrain, do so gradually and take the time to gather terrain-specific information. Check-out our CAC Field Team`s observations from the Harvey Pass area in our South Rockies discussion forum. Your reports from the field are also highly valued. Any observations can be sent to: [email protected]