Avalanche: Hatcher Pass

On third ski cut (leap-frogging entrance into line) off NE side of peak 5100, a soft slab avalanche fractured above the 3rd but lowest skier and propagated to either side. Avy was on a subtle, but still noticeable convexity. Bed surface was a crusty layer anywhere from about 1ft(skiers right) to 2ft deep(skiers left) that was present on similar aspects and at similar elevations we skied yesterday (unreactive at that time). Reading previous obs after today's experience, this seems to be the sensitive layer in the region.....N/NE/NW and upper elevations. Slab was soft, so it deteriorated and ran to the typical apron, taking other fresh snow with it, but not likely other slabs, layers or faces.

Our goal was to recon/ski the Delia/5100 lines after touring fairly extensively from NW 5100 couloir back to Mint trailhead the previous day. We looked at N. face Delia and decided to tour to the saddle between 5100 and Delia, then ski NE face of 5100 first, N face of Delia second. We noticed no red flags other than scattered skier/snowmachine triggered slides mostly N and W of the mint TH with none in the arkose zone.
From top of 5100, skier 1 made entry cut and stopped in safe spot. Skier 2 made cut to skier 1, then an additional 2 cut-turns to next safe spot. Skier 3 then bypassed skiers 1 and 2 with intent of more cutting to 3rd safe spot, but below skier 2 and before next safe spot the slab popped above. Avy bag was deployed and skier was swept onto backside and started to gain speed, but shortly after was able to engage skis with the avy bed and ski out/slow descent until the debris passed. Carried perhaps 30yrds? avy bag not truly utilized. We were all still within voice-range, so we discussed options then cautiously and uneventfully skied out.