The persistent weak layer (PWL) in the upper snowpack is the main concern. Though it's out of sight, it should not be out of mind.
Variability in test results fuels uncertainty in this layer, and as a result, necessitates a cautious approach in the field.
Last week's storm buried a persistent weak layer (PWL) that consists of suncrust, facets and/or surface hoar in some locations. Warm temps promoted the settling of a cohesive slab on top of this layer. Snowpack tests in less-traveled zones have shown the slab is reactive to human triggering.
Loose/dry surface sluffing is easily initiated by rider traffic.
The warm, wet cycle from earlier in the week triggered avalanches up to size 3.0, gouging to ground at lower elevations where the snowpack had become isothermal.
Up to 5cm of snow recently buried variable surfaces, including a breakable crust, widespread surface hoar, and sastrugi in the Alpine.
Lurking below this is a persistent weak layer (PWL) of surface hoar, facets and/or suncrust (Jan 30th) 50-80cm down. Feb 16 is another PWL (facets/crust/surface hoar) down 30-40cms. Both of these layers are reactive to human triggering, and are present/reactive in lesser traveled areas within the park (ie Bostock Pass).
A brief period of high pressure before an incoming storm on Sat & Sun.
Tonight Alpine low -9°C. Westerly ridge winds 15km/h. Freezing level (FZL) 600m
Fri Mix of sun and cloud. Alp high -5°C. SW wind 20km/hr. FZL 1600m
Sat 13cm. Alp high -4°C. SW wind 30-70km/h. FZL 1500m
Sun 25cm. Alp high -3°C. Ridge winds SW 25-75km/h. FZL 1600m
