Collapses and explosive triggered slides at Irwin

CB Avalanche Center2016-17 Observations

Location: Kebler Pass Area
Date of Observation: 01/28/2017
Name: Irwin Guides
Subject: Collapses and explosive triggered slides
Aspect: South East, South
Elevation: Near treeline

Avalanches: SS-R1-D2-AE-O 30-100cm deep crown X 40ft wide, 36* bed surface at start zone. As it ran over the cliff it triggered a ~100cm slab below on the apron, which is very similar aspect & angle as yesterday’s D2 below Pre-Evac/NC Apron. F-4F-1F slab over thin FC layer resting on smooth, untraveled MFcr.

Below Thin Line:
SS-R1-D1-AB-O ~30cm deep X 80Ft wide X ~45ft high pocket that stopped
on treed bench. Same layering as on Bender slide
Snowpack: 3 collapses: 1 Medium collapse with ~35ft shooting crack ~45cm down (same layering as above) ~60ft West of the D1 below Thin line on ~20* bench. This was after a 6# hand charge (60ft above crack) at the base of the cliff dropped a sizeable cornice that ran ~250ft downhill & did not collapse this layer. 1 small collapse on Crotch ~30* slope after 1st cover shot ~15ft away from crater. Below Dogleg RT on Sunny shoulder: Small collapse on ~*30 top of rolls over 1 snowpit on Sunny Shoulder RT, Thin rocky spot 1/2 down slope, HS 105cm, bottom 60cm FC ~3mm, above: alternating Mfcr & FC layers. ECTN