1 to 3ft Deep Skier Triggered Avalanche

CB Avalanche Center 2017-18 Observations

Location: Paradise Divide Area
Date of Observation: 02/25/2018
Name: Evan Ross

Subject: 1 to 3ft Deep Skier Triggered Avalanche
Aspect: East
Elevation: 9,500ft to 11,400ft

Avalanches:

Positive feedback on the avalanche problem for once. No obvious signs to instability yet again traveling through the terrain. On our second run we were skiing a line with the intention to trend left for an easier exit. When the first skier kept trending skiers right I had a WTF moment as that was not the direction we wanted to go. The remaining group had a quick chat as to whether we wanted to follow them and of course the double date ski stayed together. Upon regrouping we realized he was trending skiers right to avoid a big terrain trap face thing that wasn’t obvious before. We chatted about whether we wanted to descend the steeper slope that ended in a gully feature and was in the direction that we wanted to head. However it was fairly quick for the group to rule that out as a not so sweet looking slope and setup. So we kept skiing in the safer terrain heading in the wrong direction. Near the bottom of the terrain the 3rd skier trended more in the fall line as the total slope size decreased. The 4th skier followed suit and triggered a Persistent Slab avalanche breaking at the ground. 1 to 3ft deep crown breaking at the ground. The avalanche was relatively small giving the smaller scale of the slope. However it could have been large and deadly had we skied the larger slope that was in the path of our intended decent. This was a windward exposed slope from down valley winds. You definitely couldn’t tell that just by looking at the terrain given all the recent fresh snow in February. However the HS was shallower then average on that terrain feature.

Weather: Mostly Cloudy. Clearing slightly throughout the day. Gusty moderate down valley winds transporting snow.
Snowpack: Continued, no obvious signs to instability. HS in the 180 to 200cm+ range. Had the probe out trying to fine the suspect snowpack structure to dig on, but simply couldn’t get into suspect terrain safely for a targeted observation. Mostly working up a broad and open ridge feature with slope angels generally below 35 degrees. Snowpack structure was variable form past extreme wind events from earlier in the season. The tops of the most concerning northeasterly aspects had HS depths around 200cm, partly due to tree fences and old disgusted wind wales behind those features. The concerning structure would have been further down slope and too deep into the dragons den for safe observation gathering.

Photos:

Looking from the Slate River towards the large and destructive natural avalanche reported in Redwell Basin. This avalanche looked very wide propagating, but didn’t run as far down the total avalanche path.

Looking up towards the reported large and destructive natural avalanche in Baxter Basin. The crown and debris are already filling back in.

Skier triggered avalanche on Easterly facing slope, 9,700ft elevation, slope angle in the mid 30 degree range. Triggered by the 2nd skier on slope. ASu-R1-D1.5-G