This obs intends to corroborate the obs from 3/27 regarding wind slab on Broad's Fork Twin, and to provide a bit more perspective. I'll call the party that submitted the obs 'Party 1.' If you're looking for a simple data point, it's at the very end of this obs.

We were not far behind Party 1 at around 10:30 or so when we gained the ridge between Jepson's and Twin and noticed the first wind slab avalanche of the day. Earlier, we observed wind loading from the west transporting snow onto the E Face of Twin. This raised eyebrows and we continued to move toward Twin with the plan of re-assessing the wind situation along the way.

As we neared the ridge between Jepson's and Twin, we noticed some party (not certain if it was party 1 but their obs suggests it was) triggered a small, shallow wind slab (4-8in) on the NE facing slope leading up to the ridge. We felt this wasn't large enough-- and the snow wasn't heavy enough-- to make us turn around. In retrospect I am not sure if this was the right call but we continued forward nevertheless. We then booted up the bed surface of that shallow avalanche and gained the ridge proper.

Atop the ridge we observed party 1 booting out of the south bowl of Twin. It wasn't until we booted down into the south bowl itself that we noticed the sizable wind slab avalanche that caught and carried a member of party 1. Feeling the damage was already done, we made the decision to continue in their tracks and gain the summit of Twin. Again, not sure if this was the right decision, but party 1's bootpack seemed to lessen our uncertainty of triggering any remaining hangfire. We experienced no wind slab avalanches while following party 1's bootpack.

Near the summit we watched party 1 ski the E Face in a conservative fashion, dropping one at a time and skiing across slope to perform ski cuts. These ski cuts seemed effective in triggering small wind slabs. None of them looked substantial enough to knock the skiers off of their feet, but they did run fast and far all the way to the bottom of the apron.

On the summit we noticed that each member of party 1 made it to the bottom of the slope safely, and we spent some time on the summit assessing the situation. Ultimately, we chose to ski the E Face in the same fashion-- conservatively, and by performing ski cuts with each pitch of skiing. My partner and I both managed to trigger more small wind slab avalanches that did not knock us off of our feet, but again ran fast and far. Once below the headwall, the lower choke was far less reactive and we did not trigger any wind slab avalanches.

With all of this being said, I think we were lucky being the second party to ascend Twin Peaks via the ridge that day. Specifically, party 1 had to bear the brunt of 'testing' the slopes first during their bootpack. Unlike us, they did not have such clear evidence off of which they could base their decisions. We did, but did we make the right call by following them? I don't know. Of course, the simpler solution for our party would have been to back off. Indeed, wind slab avalanches are red flags and almost any newly-minted KBYG student could tell you that. Alas, we made the equation more complicated by reasoning that: 1.) the wind slabs were small and seemingly manageable; 2.) the runout consequences were acceptable.

TL;DR-- lots of shallow, wind slab reactivity noted on all aspects of the compass at the head of Broad's Fork at ~10.8k to 11.3k.