South Columbia

Assess for unstable conditions at higher elevations in your riding area.

THURSDAY NIGHT: Increasing clouds with no precipitation, 10 km/h south wind, alpine temperature -4 C.

FRIDAY: Mostly cloudy with no precipitation, 10 km/h southwest wind, alpine temperature -1 C, freezing level rising to 1900 m.

SATURDAY: Mostly cloudy with isolated flurries, accumulation 2 to 5 cm, 20 km/h southeast wind, alpine temperature -1 C.

SUNDAY: Cloudy with rain or snow, accumulation 5 to 10 cm above the snow-rain line, 20 km/h south wind, alpine temperature 0 C.

Widespread wet loose and wet slab avalanche activity was observed on Wednesday during the warm spell. Similar activity is not expected for Friday under cooler and cloudy conditions.

A few large (size 2) persistent slab avalanches were also triggered during the warm-up, being 70 to 100 cm deep and on northerly aspects around 2300 m. Looking forward, riders could still trigger this layer where it exists.

Above around 2200 m, 5 to 15 cm of recent snow may have formed small wind slabs in lee terrain features from southwest wind. Below 2200 m, a hard melt-freeze crust or moist snow exists.

A weak layer may be found around 50 to 100 cm deep. The layer consists of surface hoar crystals in treeline terrain on northerly aspects or weak faceted grains above a hard melt-freeze crust on sun-exposed slopes (i.e., east, south, west). It has been reactive between 1800 and 2300 m but given the recent rain, it is most likely to be triggered between 2000 and 2300 m. It should still be treated as suspect if you find it in your riding area.

The remainder of the snowpack is well-bonded.

• Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
• Carefully evaluate steep lines for wind slabs.
• When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.