This avalanche occurred sometime during the morning of December 24 on a steep northeast-facing, wind-loaded slope. There were two adjacent tracks above the crown, so it is possible the riders intentionally triggered the avalanche. What caught my attention was the 30-35 cm deep slab was not that strong - at most 4F+ hard and just above a faceted layer that was buried on December 13. The persistent weak layer (PWL) is so weak that in some places, the slab has to be just "strong enough" to avalanche.