Half Phantom and Moraines

Had a great day in the Sherbrooke Lake/Ogden area. We initially aimed for the Phantom Couloir. Burried soft windslabs (4F) in the moraines made us go the long way arround. A SZ 2.5 debris covered with 5 cm of new snow was observed covering the fan of the Phantom to the bottom. A few larger hard chunks in the debris indicated that the avalanche (24 hrs old) had likely been triggered by a cornice fall. At ridge top on the right side of the couloir, only one tiny cornice remnant could be observed. No wind transport could be seen at ridge top in the early morning and no wind could be heard or felt either. So we decided to push upward. When about halfway up the couloir, light wind transport was noticed at ridge top and two size one sloughs came down naturally. The initially slough controlled snowpack changed to 50+ cm of unsettled snow around the same time. We called it quit fearing that a slough could start higher and gather mass before reaching us. The ski down the moraines was so good that we climbed back to the top of the moraine two times more upon reaching the Xmas tree pitch. Including us, 15 people skied the main line/small bowl and gulley from the top of the moraines. The skiing was all time. The ski down the Xmas tree pitch had some excellent snow to the bottom (the lake). Coverage was excellent on the ski out from the lake to the parking lot.

Observed two SZ 2 loose dry avalanches that originated from unskiable terrain spilling over cliffs and covering the moraines closest to the cliffs. They were both triggered by windloading at ridge top.

Snowfall S-1 starting as we reached the moraines. Winds, initially calm, picked up at ridge top mid morning. Snowfall eventually stopped but wind remained in the moderate range at ridge top with a couple drafts making it down to the more sheltered moraines.