Touchy wind slab over Facets

While guiding in the area, we witnessed a party of two remotely trigger a sz 1.5 slab avalanche from 50m away on a steep shaded North aspect face below a vertical head wall. 20-30cm crown (estimated), likely on facets. This slope is constantly in the shade, an ideal facet factory. Despite the prevailing spring conditions, winter problems still exist, stay sharp!
In general, we found an average of 10cm cold, dry snow above 2000m from Crowfoot pass down to tree line as we handrailed the headwall. Some whumpfing and cracking in the faceted snowpack in flat terrain.
No cornice activity observed despite the clear, sunny day.