ACMG Training and Assessment Program – Trip Report
April 1–7, 2025
Blackcomb Backcountry, Mystery Creek, and Duffey Lake Regions
The ACMG Training and Assessment Program spent the past week ski touring in the Blackcomb Backcountry, Mystery Creek, and Duffey Lake regions.
Weather & Conditions
In the days leading up to the program, the Coast Mountains experienced a significant rain event that extended to mountain tops. Fortunately, cooling temperatures followed, accompanied by 10–20 cm of new snow over a widespread crust. We began the week with unsettled conditions and a strengthening ridge of high pressure.
High north-facing terrain offered excellent skiing, particularly in lower-angle features. By mid-week, the ridge was well-established, bringing clear skies, rising freezing levels, and significant solar input. The onset of a classic spring diurnal cycle increased our confidence in overnight surface freezes and provided good corn skiing on solar aspects.
Later in the week, the ridge broke down with the arrival of a low-pressure system, bringing strong to extreme southwest winds and up to 30 cm of new snow. Precipitation arrived with warm temperatures but gradually cooled, setting us up for another period of excellent skiing.
Snowpack Summary
The March 27 melt-freeze crust (MFcr) defined the snowpack structure, with a 5–20 cm thick crust observed up to ~2600 m.
Northerly aspects held 10–30 cm of 4F–F snow over the crust.
Solar aspects developed a melt-freeze surface crust (MFsc) up to ridge crest due to sustained solar input.
The April 6 storm produced an upside-down snowpack in many areas, with up to 20 cm of moist snow overlying a variety of previous surfaces — including sun crusts, isothermal snow, moist snow, and wind-scoured patches down to the March 27 MFcr.
Glacier coverage remains excellent, with depths exceeding 3 m in all areas travelled. Snow depth decreases rapidly with elevation loss, averaging 200–250 cm at treeline.
Crevasse bridging was reliable due to both coverage and snowpack structure. Cornice hazard was a primary consideration while approaching high alpine features. In the lower elevations below treeline, low tide conditions and heavy, moist snow required mindful skiing to protect knees and equipment.
Trip Summary
April 1–2 – Duffey Lake Region
Groups toured and skied in the Cayoosh, Anniversary, Matier Glacier, and Tszil North Glacier areas. Access trails to Joffre Lakes and Keith's Hut remained passable but were becoming challenging with melt-freeze cycles and deteriorating snow cover.
April 3 – Whistler Blackcomb Backcountry
Groups travelled in the Spearhead Range, including the Phalanx, Decker, and Trorey zones.
April 4–5 – Mystery Creek Area
We flew into the Mystery Creek region and travelled through the Hibachi North Basin and Mystery Glacier zone, taking advantage of excellent conditions and coverage.
April 7 – Whistler Blackcomb Backcountry
Groups returned to the Whistler Blackcomb backcountry, skiing in the Disease Ridge, Circle Lake, Decker, and Vista zones.
Mike Adolph
Eric Ostopkevich
Todd Anthony-Malone
