Simpson North / Vermilion Crossing

Ascended north of the "Simpson" Avalanche Paths in the burn aiming for the north end of the ridge facing the highway- starting from Vermilion Crossing DUA. Found light snowfall at the road with 3cm on a thick crust out of the parking lot. By 1600m we had 10cm of snow since Feb 8 on a thin crust with another 10cm to the Jan 24 surface hoar that sat on a second crust. At 1700m the upper crust was gone and the lower crust was thin with the snow local to our skis starting to crack and small settlements occurring on the surface hoar and crust down 20cm. The terrain above 1750m becomes steep and as we climbed, cracks would propagate up to 20m away with the slab peeling off between the first 3-4m of switchebacks. On a bench at 1800m we found the crust below the surface hoar was gone. We tucked into a smaller roll and dug. - Profile attached and description in snowpack tab- We turned around from the pit and ski cut our way back through the steep terrain. On the first 37ish degree role, we triggered a 15m wide soft, sluggish slab that quickly broke up and pushed the top 25cm 50m until the debris piled up on a bench. The next roll was only about 30 degrees and nothing failed. Skiing was good until about 1600m and then became a bit racy in the blow down back to the truck with 5cm sitting on the crust.

Ski cut the soft slab on the surface hoar 25cm deep that went 5-10m on either side of skis. Sluggish and slow moving initially, failing as chunks a few feet wide but once in motion, these broke up to push the surface snow with increasing speed and width while the slope angle remained steep. Lost steam as the debris piled up onto a low angle bench below leaving a pile 25m wide.

Profile on a 37 degree slope at 1800m. Dug to ground 165cm. Found 10cm of fist snow from this week sitting on another 8 cm of faceted 4F snow above somewhat heat-affected surface hoar sz 10 standing proud. This soft slab sat on 1F- snow. Compression tests failed on the first and second hits- sudden collapse- on the surface hoar, although we could not pick up more than half of the block without it falling apart. An extended column test fractured the width of the shovel on the second hit, then 30 cm further on the 3rd hit and to the end on the 11th hit. We found remnants of the Jan 3 surface hoar down 52cm but had no results on this layer. The Dec 15 crust was a solid icy mass 1 inch thick down almost 1m. The November crust sat almost 20cm off the ground with moist, rounded depth hoar mixed into the willows against the ground.