Cornice Triggered Avalanche Mt Owen

CB Avalanche Center2019-20 Observations

Location: Kebler Pass Area
Date of Observation: 03/05/2020
Name: Joey Carpenter
Subject: Cornice Triggered Avalanche Mt Owen
Aspect: North, North East, South
Elevation: 11.4-12.8

Avalanches: Large cornice fall (estimated) late yesterday triggered widely propagating slab in recent storm snow. R2D2.5 The spx in the E facing gut off Owen was basically destroyed from the massive blocks running through. First photo from toe of debris pile shows the multiple smaller storm slabs that released as a result of the massive impact from the cornice failure. Second photo from the bench below Scarps Ridge shows the lower storm slab released by the huge chunks bouncing (bounce impressions indicated in green) past the end of the debris pile, over the next roll and onto the bench (blocks indicated in orange). The last photo, with sled for reference, shows how large these pieces were (these are the blocks indicated in orange in previous photo). The three remaining chunks that hadn’t been destroyed over their 1500 vertical foot journey downhill were still about the size of small sedans.

Weather: Single digits to start the day at the TH but rapid warming. By the time we were on our second ascent of the morning, it was skinning/booting in tshirt weather. Snow near rock out croppings was beginning to let go although we didn’t observe any rollers from snow surface warming.

Snowpack: Southern ascent held a firm base, with boot top penetration through a ~5cm breakable crust. N & NE snow surfaces have settled to 7-9 inches of snow and feel much more “wintery” than solar exposures. Overall supportive spx with no underfoot signs to instability. The cornice fall did indicate there are still some surface slabs that could potentially release but may require intense impact to do so.