Two persistent weak layers in the upper 80cm of the snowpack are reactive to human triggering, especially in zones with little human use.
These have been observed at Treeline and below, with Parks field teams able to remote trigger or ski cut unsupported rolls up to size 2 avalanches.
Stick to conservative, supported lines.
Recent moderate south winds loaded lee features near ridgetop. Be careful as you transition into wind-affected terrain. Wind slabs may be most reactive on solar aspects where they sit on a crust.
A reactive surface hoar layer, down 30-50cm, is touchy to human triggering.
A second layer of surface hoar (up to 40mm below treeline) is buried 50-80cm deep and sits on a crust.
Use caution in terrain that has not seen recent rider traffic - this is where triggering is most likely.
A field team on Abbott was able to easily ski cut touchy slabs from low angle terrain to sz 2 on unsupported rolls. Propagation was up to 30m across, 40cm deep.
On Monday, a field team remote triggered a sz 2 slab, 60-70cm deep, into Bostock Creek from 10m away. The debris snapped small trees near its toe.
Also on Monday, a notable sz 2 avalanche in Cougar Creek East caught and injured a rider, with the slab failing ~40cm down. This was likely on the Feb 9 surface hoar.
Up to 60cm of new snow fell this past week. Ridge-top winds created slabs in immediate lee features.
The Feb 9 surface hoar (SH) is buried at the bottom of this new snow (40-60cm down) and is reactive in tests.
Recent Spring-like temps and sunshine created several crusts in the upper snowpack, upon which the Feb 9 SH sits.
The Jan 26th layer, composed of surface hoar/facets/crust, is buried down 60-80cm. The largest surface hoar is preserved in sheltered areas below treeline.
Cooler Arctic air moves into the region, lowering the temps. Expect a mix of sun/cloud with even the chance of isolated flurries.
Tonight: Clear. Alp low -14°C. Winds S 10km/h. Freezing level (FZL) valley bottom.
Wed: Sun & cloud. Alp high -12°C. Winds W 15km/h. FZL 600m.
Thurs: Sun and cloud. Alp high -16°C. Ridge winds light. FZL valley bottom.
Fri: Sun and cloud. Alp high -14°C. Ridge winds light. FZL valley bottom.
