2018/05/02 - Alaska - Upper Blackstone Glacier, south of Whittier

Published 2020/01/02 by Wendy Wagner - Forecaster, CNFAC

Based on slab depth (2’ estimate) and density it is most likely this avalanche was composed of a layer of storm snow from the end of the storm cycle.  Riders did report about 2’ of storm snow on a “crusty layer” the day of the avalanche.  It is possible the Westerly winds the day prior added additional wind drifted snow to the slab shortly before the avalanche.  This wind loading coupled with direct sun on the slope for much of the day may have increased the instability of the snowpack on this Easterly aspect.  The weak layer of the avalanche is unknown, however it is suspect that there were buried crusts from springtime warm temperatures that may have occurred mid storm cycle.

On Wednesday May 2nd a group of six snowmachiners left the Whittier trailhead at approximately 10:15am.  They had a rough plan to meet up with another group of four riders (who were an hour behind) on the Blackstone Glacier for a day of sunshine and spring riding to end the season.  All members of both parties were advanced riders and all were familiar with the area.  Everyone in the original group of 6 carried avalanche transceivers and most carried shovels and probes.  Two people in that group had avalanche airbags (Riders 3 and 4).

By early afternoon the complete group of 10 had met up, were playing, and riding in the same general area, although not necessarily all together.  Around 3:30pm two riders from the group of 6 had departed en route back to the trailhead with the understanding that everyone was beginning to move that way. Note: At this point, this accident summary assumes the group of 6 riders is now a group of 4 that were in the immediate vicinity of the avalanche.  

At approximately 3:40pm Rider 1 and Rider 2 crested over a sub-ridge and descended into a gully (Image 1) en route back to the trailhead.  Simultaneously Rider 3 was side-hilling/ascending the same gully and crested above Rider 1 and 2. 

With three people on the slope at the same time and in fairly close proximity, it is unclear from where exactly on the slope the avalanche was triggered.

Rider 4 was out of the way in a safe zone, and witnessed the avalanche initiate and propagate about 200’ above where Rider 3 was on the slope.  Rider 4 described seeing Rider 1 and 2 disappearing and reappearing in the moving debris.  None of the 3 Riders on slope saw or heard the avalanche until it hit them.  Rider 3 (highest on the slope) was immediately thrown from his sled and was able to successfully deploy his airbag backpack.  He came to rest mostly on the surface, with just his legs buried and separated from his machine by 50’ or more.  Rider 1 was about 10’ behind Rider 2 when the avalanche hit them both from behind.  Rider 2 describes getting spun 360 degrees on his sled as the debris hit him.  He quickly realized he was in an avalanche, got his bearings and pinned the throttle in an effort to power out of and ahead of the moving debris.  He described the next several seconds as diving under the snow then resurfacing before diving again.  Rider 2 never separated from his snowmachine and came to rest near the toe of the debris still clutching his machine and buried up to his armpits/ neck with one hand free.  Rider 2 and 3 were uninjured.  All three machines were fully or mostly buried once the avalanche came to rest.

Rider 2 was able to extract himself in less than a minute and scanning the debris, he saw Rider 3 (airbag deployed) on the surface and what he recognized as Rider 1’s glove breaking the surface and still moving.  Rider 2 was the first to make contact with Rider 1’s moving hand and began digging toward where he thought his face was.  Rider 2 was able to establish an airway (helmet strap off and cleared snow from Rider 1’s mouth) within approximately 2.5 minutes of the initial burial.  About this time Riders 3 and 4 were on scene and continued to help extract Rider 1.  The group estimates that Rider 1 was on the surface and CPR underway in less than 5 minutes from the initial burial.  CPR continued for 20-30 minutes until it was decided to send rider 2 to find a cell signal and make a 9-1-1 call.  Rider 2 located the group of 2 who departed minutes before the avalanche.  They had a working cell phone and emergency medical services were notified.  Roughly 30-40 minutes after the avalanche, several other riders from a larger group began to show up on scene and offer resources.  

Ultimately the 210th Rescue squadron helicopter was dispatched and launched from Anchorage (JBER Airforce base).  CPR was continued as Rider 1 was transported onto the helicopter and flown to Providence Alaska Medical Center in Anchorage.  Rider 1 was declared deceased upon arrival at the hospital.

There is no avalanche forecast for this area. The closest forecast covers Turnagain Pass, issued by the Chugach National Forest Avalanche Center (CNFAIC).  The CNFAIC’s last forecast of the season was on April 26th.  On April 28th a ‘Springtime Avalanche Tips’ bulletin was issued for the remainder the season.  On May 1st, a day before the accident, the CNFAIC posted  Facebook message warning backcountry travelers of heightened avalanche danger region wide.

We would like to express a sincere thank you to the group involved in this avalanche.  Their willingness to share the events and several photos to compile this report was invaluable.