The South Coast has been bit by some intense snow and rain, which is keeping danger elevated. Avoid avalanche terrain.
A widespread weak layer consisting of a crust, with facets and/or surface hoar on top of it is now down about 125-175 cm. This layer is expected to produce large avalanches for longer than what is typical after a storm on the South Coast.
Fresh and reactive storm slabs are expected to be widespread and easy to trigger.
MONDAY NIGHT - Snow and rain, 20-30 cm/mm / strong southwest wind / alpine low temperature near -1 / freezing level 1200m, falling to 800 m overnight
TUESDAY - Flurries, 5-10 cm / moderate southwest wind / alpine high temperature near -2 / freezing level 700 m
WEDNESDAY - Mainly sunny / light northwest wind / alpine high temperature near -4 / freezing level
THURSDAY - Snow, 10-15 cm / strong west wind / alpine high temperature near -4 / freezing level 500 m, rising to 1000 m in the afternoon
Natural avalanches are expected on Tuesday, and due to the presence of a persistent weak layer, they could be very large.
It has been a busy week for avalanche activity in the South Coast mountains, with natural and/or human triggered avalanches reported every day since last Monday. These avalanches have failed on the persistent weak layer that was recently buried.
North Shore Rescue responded to a serious, but non-fatal avalanche incident last Tuesday evening on Cypress Mountain. One person was involved and was partially buried. The avalanche was a size 2 storm slab on a west aspect at approximately 1100 m and failed on the recently buried weak layer.
20-30 cm/mm of precipitation is expected for Monday night, with falling freezing levels bringing some snow back to lower elevations. Around 5-10 cm is expected on Tuesday.
There is now about 125-175 cm of snow sitting on a widespread persistent weak layer. This weak layer consists of a crust that also has weak facets and surface hoar on top of it in many areas. This layer will probably take more time to gain strength than what is considered typical for the South Coast region.
Click here to watch North Shore Rescue's January 29 snowpack discussion, which illustrates this concerning snowpack structure.
