Widespread Whumpfing on Hidden Peak

As soon as we left the parking lot at Hidden Peak, we could feel a wet heavy layer of snow resting on top of lighter storm snow each time we took a step or planted a pole At the trailhead, it had obviously rained at the end of the storm and left some runnels and very wet snow on the surface. Evidence of rain existed up to just below 7000 ft.

Below ~6800 ft. we did not find much old snow underneath the storm snow, just a crust at the ground. Once we got above 6800 ft, we started to feel a mix of crusts and old weak snow (facets) below the storm snow. At 6900 ft. we felt our first small whumpf as the facets below the new snow collapsed. At this point, only about 18 inches of new snow existed on top of the facets. As went higher, the new snow got deeper, the facets became more developed, and the whumpfing become larger and more widespread. Between 7000 ft. and 8000 ft. we triggered a whumpf about every 10 minutes. We also found unstable results on the facets in a snowpit test (ECTP - see video). Some of the whumpfs were small and some traveled at least 100 ft away from where we triggered them. Some cracking also occurred with the largest whumpfs. The easiest places to collapse the buried weak layer were near trigger points but the collapses also happened in other places. Near 8000 ft, the facets were up to 2.5 ft below the surface. In addition to these whumpfs, we also triggered some cracking as the layer of heavy dense storm snow broke away from the lighter snow below it. Above  8000 ft, the whumpfs became less frequent but larger up to about 8300 ft on northerly aspects. We also felt a small whumpf on an ESE facing slope at ~8300 ft. We dug a quick snowpit there to see what had collapsed. It turned out to be the heavy storm snow breaking away from the lighter storm snow below it (ECTP 10) not the facets at the base of the new snow.

Above 8300 ft, the whumpfing died away. By this point, the new snow totals approached 3 to 4 ft in some places and the facets below them were less developed. The layer of heavy storm snow was also close to 1 ft. thick at these higher elevations. We did some more snowpit tests on a N facing slope at 8840 ft. We got unstable results as the heavy storm snow broke away from the lighter snow below it (ECTP 5) and results indicating that if a large enough trigger could start a fracture in the facets that fracture could propagate along the weak layer (PST 45/100 END 85-90cm below the surface). 

Throughout the day, we made sure to set a skin track that only used terrain less than 30 degrees in steepness with nothing steep above it. While one of us broke trail the other kept an eye on the inclinometer to make sure we did not stray into or below steeper terrain.  When we descended, we followed our skin track line back down to the car to make sure we stayed in low angle terrain. At the upper elevations where the heavy snow would mostly support our weight on skis, travel was decent, but as we descended the heavy snow layer got wetter, stickier, and less supportable making skiing challenging and strenuous.