Last First Tracks: Snowmass Memorial Held for Patsy Hileman

A memorial was held on 5 January for Patricia Mae “Patsy” Hileman of Snowmass Village, Colorado. Patsy, a 26-year veteran of the Aspen Ski Patrol, died in an avalanche on 30 December in the Ship’s Prow Glade, a backcountry skiing spot at Aspen’s Snowmass area. The memorial service celebrating her life was held on at the Elk Camp restaurant at Snowmass Mountain. Snow Mass Ship's Prow Approach

Hileman appears to have inadvertently triggered a portion of the “crown” from a previous avalanche that pushed her off the edge. She was skiing in a section of the Snowmass backcountry that is not explicitly open to the skiing public due to its inherent dangers. A previous avalanche at that location had been triggered with explosives by the patrol on 27 December 2012, three days before Hileman’s incident. While the avalanche was very small, it appears to have been of sufficient size to sweep Hileman, an expert skier familiar with that area, off the cliff’s edge.

Patsy, born 18 February 1963, was a Michigan native. She moved to Snowmass Village in 1985 after graduating from Michigan State University with a B.S. in Animal Husbandry. Patsy’s family noted that she was an avid backcountry skier, hiker and biker, and was a fixture on the ski slopes, even on her days off. Friends and family are invited to sign the online guest book at her memorial site. Donations to the Patricia Hileman Memorial Fund will be used to create a public memorial in the Snowmass Village commemorating Patsy’s life. Patsy-Hileman

Avalanche investigators were unable to conclusively determine all facts preceding the incident. They visited the site about 24 hours after the accident, and at that point three avalanches had come to rest on the slope below, including the explosive-triggered avalanche on the 27th; the avalanche involving Hileman; and a small event that was triggered by rescuers searching for Hileman.

There were no eye witnesses to the incident, but investigators were able to examine Hileman’s ski tracks (Patsy’s tracks shown in the first photo above) descending through the Ship’s Prow Glade. She apparently skied to the bottom of the glade and onto the crown of a previous avalanche. That crown was directly below two small stands of trees, and when she passed through those trees and onto the crown, it gave way. Investigators concluded that Hileman likely triggered a portion of the crown on a 40 degree slope.

Colleagues of Patsy Hileman last saw her working the morning of the accident, at around 10:30 am. A member of the Snowmass patrol tried to reach her after 12:30 pm by radio but did not get a response. The search was initiated at 12:45 pm, where a number of two-person patroller teams split up and searched likely locations near where she would have been patrolling. One of those teams located Patsy below the Ships Prow cliffs at 1:23 pm, lying face down on the debris pile from the previous slide. First aid was administered immediately by patrol paramedics in contact with a remote local physician, but they were unable to revive her.

Patsy-Memorial

The photo above was taken at Patsy’s Saturday evening memorial. Aspen ski patrol members held flares spelling-out Patsy’s name on the hill at Snowmass to honor their colleague.

Patsy Hileman memorial site link

Avalanche scene photo from the Colorado Avalanche Center report

Avalanche scene photo from the Colorado Avalanche Center report


Colorado Avalanche Information Center Report

Avalanche Details

Location: Ships Prow Glades, Snowmass Ski Area
State: Colorado
Date: 2012/12/30
Time: Unknown
Summary Description: 1 ski patroller killed
Primary Activity: Ski Patroller
Primary Travel Mode: Ski
Location Setting: Ski Area – closed area

Number

Caught: 1
Partially Buried, Non-Critical: 0
Partially Buried, Critical: 0
Fully Buried: 0
Injured: 0
Killed: 1

Avalanche

Type: SS
Trigger: AS – Skier
Trigger (subcode): u – An unintentional release
Size – Relative to Path: R1
Size – Destructive Force: D1
Sliding Surface: O – Within Old Snow

Site

Slope Aspect: NE
Site Elevation: 11200 ft
Slope Angle: 40 °
Slope Characteristic: Unsupported Slope

Avalanche Comments
The skier triggered a portion of the crown from a previous avalanche. The previous avalanche was triggered with explosives on December 27, 2012, three days before the accident. The skier-triggered avalanche broke into the depth hoar layer near the base of the snowpack. The avalanche was quite small in size, but probably large enough to move the skier over the edge of the cliff below.

It was not possible for us to determine the exact dimensions of the avalanche that swept the skier over the cliff. By the time we visited the site (~24 hours after the accident) three avalanches had released on the slope. The explosive avalanche on the 27th, the avalanche that produced the accident, and a small portion of the crown triggered by rescuers while searching for their missing colleague. We estimated the size of the avalanche by examining the site and interviewing people who had seen one or more of the three avalanches. We determined the path of the skier and the likely trigger point from ski tracks, the remaining crown, and slope characteristics.

Weather Summary
The morning of December 30th started with clear skies and temperatures between 10-15 F at treeline on a nearby weather station at the Snowmass Ski Area. No new snow had fallen in the previous 24 hours. Winds were out of the southwest averaging 15 mph with gusts between 25-35 mph. Cloud cover increased throughout the day ahead of a storm moving along the southern border of Colorado.

November of 2012 was a generally dry and mild month with only one significant storm. The Snowmass Ski Area picked up about 12 inches of new snow between November 9th and 11th. After that storm cleared, mostly dry and mild weather conditions dominated the next four weeks. During the first week of December, weather patterns changed and the Snowmass area experienced more frequent snowfall with storms moving through about every three to four days through the end of the month. In the days leading up to the accident, the Snowmass Ski area reported 12 inches of new snow between the 27th and 28th.

Snowpack Summary
Snow from early November followed by a several weeks of dry weather formed a fragile layer of depth hoar. Subsequent snowfall in early December through the time of the accident slowly built a slab of stronger snow above this basal layer. This stratigraphy is consistent with snowpack observations and avalanche occurrence in nearby backcountry areas and across the Aspen zone.

As part of the ski area’s avalanche hazard mitigation program, the ski patrol performed some boot packing and explosive avalanche release in this area. Boot packing aims to disrupt the basal depth hoar layer and thus decrease the likelihood of triggering an avalanche. Explosive work seeks to cause small avalanches at specific times. Both present some risk to workers, which is generally managed by a series of work-place safety procedures.

The avalanche released in an area that was unaffected by the boot packing program. It was most likely not part of the boot packing program because of its proximity to the cliff below. The avalanche broke within the crown of an explosive-released avalanche from the 27th of December (3 days prior). We made our snowpack observations on a 34º slope directly above the avalanche site. There was evidence of boot packing in our snow profile. We performed several Extended Column Tests at this site and observed fractures with a sudden collapse character on the 23rd loading step of each test. In each test we also observed horizontal cracking on loading step 13, under the load area below the surface snow layer.

Events Leading to the Avalanche
There were no eye witnesses to the accident. By examining the ski tracks, it appears the skier descended through the Ship’s Prow Glade. Near the bottom of the glade she skied on to the crown of a previous avalanche. The crown was directly below two small stands of trees. As she passed between the trees and onto the crown, the slope angle increased from 34º to 40º. She likely triggered a portion of the existing crown on the 40º slope.

Accident Summary
There were no eye witnesses to the accident. The skier’s track crossed the crown face approximately 10 m uphill of the cliff’s edge. She likely triggered a portion of the crown and was washed over the edge of the cliff.

Rescue Summary
The victim was last seen at work around 10:30 am on the day of the accident. Sometime after 12:30 pm another member of the Snowmass Patrol tried to reach her by radio and was unable to get a response. A search was initiated at 12:45 pm. Several two person teams of patrollers split up and searched likely locations surrounding her work station. Two members of the patrol found the victim below the Ships Prow cliffs at 1:23 pm by a visual search. She was lying face down on the snow surface, on top of debris from an older avalanche. First aid was started immediately and paramedics in contact with a local doctor pronounced her dead at 1:37 pm.

Full text and images of the Colorado Avalanche Information Center incident report here