General Observations

Skinned up a drainage from the road at southern Rainbow mountain. Found a well bounded, stable snow layer with a total snow depth of 160 cm, about 1/3 up a chute at 36 degrees angle, the chute varied between 36-44 degrees overall. Dug a pit and did an ECT that did not collapse or propagate. An obvious  brown colored weak layer with large facets was found about 20 cm above ground, most likely rain of snow from early in the season. Column failed on that layer when using the avy shovel to pry hard after the ECT test.

A small sluff avalanche was observed at the very top of the chute originating among a rock band at the ridge line, the avalanche propagated about 200 yards down before coming to a halt. We believe this was caused by rock fall or a corniche breaking off due to very high winds at the ridge line above (visible snow plumes). The chute held good snow but sides and the ridge line was wind blasted with little to no snow along the sides.