Ski touring around Lake Agnes. Many downed trees on hiking trail made for an interesting ascent/descent. Found variable conditions beneath Niblock. The south facing slopes had sun crust, north slopes had wind crust and temperature crust depending on the aspect, but found decent snow in NW facing couloirs. Booted the couloir under Devil's Thumb. Near the top stsrted breaking to ground with large blocks ready to slide to ground on deep persistent layer. Shown in photo. We booted back down until we felt a more stable snow pack.