Front Range

Avalanche

Myself and another skier attempted to ski Notchtop Spire Couloir. Upon arriving at the top via the Flattop trail, we found several other parties skiing the adjacent Notchtop Couloir - no avalanches triggered there. There was about 8-10 inches of new spring snow in the area that had accumulated over the past few days. On my first cut/traverse into the line I triggered a storm slab avalanche that propagated about 30 feet and ran the entire length of the line. The slab broke at an undetected problem layer of graupel/facets at the new snow/old snow interface. It ran very fast at this layer, and about 300-400 feet below where it was triggered it impacted more snow and increased the size of the slide, and ran the full width of the skier's left choke. I fortunately was not carried by the slide as i was able to self-arrest with a whippet as the slab broke. I chose not to continue skiing the line, and instead booted back out along the bed surface. Mistakes were made - I did not do a sufficiently thorough inspection of the old/new snow interface, and the amount of new snow should have perhaps given us more pause. I count myself both lucky and hopefully wiser in the future.