Observation: Mill Creek Canyon

When breaking trail in a few drainages in upper Millcreek today we experienced widespread cracking and collapsing. Notably to us, when in a drainage with a flowing creek, we had multiple collapses propagate across the creek - one that caused a very small slab to break loose right above the creek, and another that was triggered from ~ 10-20 ft uphill on one side of the creekbed and propagated upslope ~ 100 feet on the opposite side. Slope must have been just under critical slope angle, because we saw the top of the slope fully crack across, but did not release in a slide.

Pretty impressive to us that slabs were connected across the creek, and a good reminder to be really wary of small slopes in terrain traps, especially ones like these near creeks where there is probably more buried/preserved surface hoar than other locations.