The 'left variation' of crescent moon couloir.  Less steep than crescent moon for the most part; the final headwall is perhaps 45 degrees but short.  Once you top out there are numerous boulder problems one could pull to gain the summit ridge on the left side of the couloir or go a little further back to a less steep option. 

Park at the Carson Pass sno-park and head SSW, Roundtop is visible from the trail and the couloir is obvious.  When the couloir splits into two, take the left side.  

Crampons, ice axe, skis