A fatal avalanche occurred west of Golden on Wednesday. Details can be found in here. The snowpack in this region is very complex and requires sophisticated snowpack analysis, careful terrain selection, and extremely diligent group management. The only way to minimize exposure is to select low angle, low consequence terrain and avoid areas where an avalanche could propagate widely.
Wind slab avalanches are possible to trigger in lee terrain after recent snow has been redistributed by southwest wind. The bond of this snow to underlying layers is suspect.
Large avalanches have been triggered on a 40 to 80 cm deep layer of surface hoar and facets that was buried in late January. This problem seems most concerning in the western and southern Purcells, where the layer is more deeply buried and primed for human triggering. Steep open slopes should be avoided.
It remains possible for riders to trigger a weak layer of facets near the base of the snowpack. The most likely area to trigger it is in shallow areas with variable snow depths. Avoid thin and rocky start zones and select routes that avoid travelling through or under large avalanche paths.
A size 3.5 avalanche that failed on a deep persistent weakness occurred west of Golden on Wednesday and resulted in 2 fatalities. More details regarding this avalanche can be found in this report.
Additional avalanches have been reported in the last 48hrs including two size 2 wind slabs on north and east facing alpine features, two size 2 persistent slabs on east aspects above 2300 m, and two cornice failures.
Surface hoar continues to grow in open areas and a sun crust now exists on steep south aspects. Wind slabs of all ages still exist in exposed terrain and windward features are scoured. Good quality, settled powder snow can be found in sheltered alpine and treeline features. Friday could see some new snow fall onto these existing surfaces so pay attention to how that bond develops.
A variety of persistent layers still exists in the middle snowpack and continue to see avalanches occur on them periodically. Don't let these layers surprise you.
The lower snowpack contains a widespread layer of large, weak facets that is typically 80 to 150 cm deep. Snowpack depths at treeline range between 80 and 200 cm, with the shallowest depths found on the eastern edge of the Purcells.
Thursday night
Increasing cloudiness with flurries bringing 5 cm of new snow. Wind from the southwest at 15 km/h. Temperature -11˚C.
Friday
Cloudy. 5 - 10 cm of new snow. Wind from the southwest at 20 km/h. Temperature -8˚C.
SaturdayCloudy. 10 cm of new snow. Wind light and variable. Temperature -6˚C.
SundayA short clearing in the early morning then cloudy. 5 - 10 cm of new snow. Wind from the southwest 5 - 10 km/h. Temperature -13˚C in the morning rising to -5˚C in the afternoon.
More details can be found in the Mountain Weather Forecast.
