Thar Peak Critical Loading

A party of 14 observed several size 1-2.5 avalanches, on the SE slopes of Thar Peak in open trees starting in the early afternoon. The critical loading from the overnight storm was slow to consolidate, and produced slabs on the underlying ice crust. Compression tests and extended column test did not result in clean shearing or propagation on a 25 degree slope, with a pop at as little as CTE 6. Steeper wind loaded features and convex rolls saw propagation and releases from both natural and accidental skier triggering.

Multiple size 1-1.5 naturally triggered storm slab and loose dry avalanches observed during ascent to 1640m in the early afternoon. From a protected bench at 1640m we observed a skier remotely trigger a slab release along a buried ice crust at 60-70cm depth. Starting zone was convex with 30cm fresh snow loading from the overnight storm. Crown line spanned the width of a broad, funneling clearing with the runout narrowing between protected terrain. On our ski descent at 1515m a size 1.5 storm slab to the 30cm critical loading depth was released accidentally when cutting high across a 45 degree convex feature.

Skies had cleared between 12-2PM with cloud cover and light snow returning mid afternoon. Mostly calm with occasional light winds throughout the day.

Persistent weak layer observed with a crust at 60-70cm depth. Storm snow remained loose and dry into the afternoon at elevations above 1450m, consolidating into a heavier snowpack on lower slopes.

On our ski descent at 1515m a size 1.5 storm slab to the 30cm critical loading depth was released accidentally when cutting high across a 45 degree convex feature. Runout swept two members of our party resulting in partial burials. A ski was released and was buried/recovered. Majority of the party was spotting from the bench below as the first members to ski the feature sequentially dropped over the convex roll. Remaining party members spotting from above then descended via shallower, sheltered terrain.