Anyone living in or planning to head to the slopes in the Sea to Sky or South Coast areas this weekend should take note of avalanche warnings.
Large and destructive natural avalanches have already occurred on January 11.
Avalanche Canada stated on January 16 that winds have scoured exposed snow areas and redistributed snow to lower elevation areas in both areas.
An extensive number of recently formed wind slabs are expected in unexpected locations today (January 17).
South Coast region
On the North Shore, conditions were described on January 15 and 16 as "quite touchy" with five to 15 centimetre (two to five inches) storm slabs on steep slopes triggering easily by human activity.
After 25 to 30 centimetres (10 to 12 inches) of new storm snow (for a total of approximately 120 centimetres over the past few days), previously wind-affected surfaces in exposed areas and soft, low-density snow in sheltered areas were buried at all elevations. A hard-melt freeze crust is buried below, and a weak layer above this crust in some areas. Surface instabilities are expected to be found in wind-loaded areas.
In the South Coast region, avalanche danger ratings remain moderate at all elevations before they rise to considerable tomorrow (January 18) and high by Sunday (January 19).
While a mix of sun and cloud is expected today for the North Shore, flurries are expected to begin overnight, along with light winds. Tomorrow, clouds with snowfall are anticipated to bring 15 to 20 centimetres (six to eight inches) of new snow with strong winds. By Sunday, clouds with continuing snowfall is expected to bring an additonal 15 centimetres of new snow for a total of about 60 centimetres (24 inches) over two days. Precipitation may turn to light rain with moderate to strong winds easing over the day.
Sea to Sky region
By the end of the day yesterday (January 16), approximately 35 centimetres (14 inches) accumulated in the Sea to Sky region.
This new snow buried previously wind-affected surfaces in exposed areas at all elevations, including soft, low-density snow in sheltered areas. The new snow added approximately a meter of storm snow that accumulated over the past week and had been affected by substantial winds in exposed areas. The base of the snowpack consists of hard melt-freeze crust and lower than average precipitation led to a layer of sugary-faceted grains.
These layers remain sensitive to being triggered by human activity on steep and unsupported slopes or around sheltered shallow, rocky start areas.
Today in the Sea to Sky region, avalanche ratings are moderate below the treeline and considerable in treeline and alpine elevations. However by tomorrow, avalanche potential will rise to considerable below the treeline and to high in alpine areas (treeline areas will remain considerable). On Sunday, high danger ratings are forecast for all elevations.
Meanwhile, the weather forecast for the Sea to Sky area includes clouds with flurries and light winds tonight. Tomorrow, clouds with continuing snowfall is anticipated to bring about 15 to 25 centimetres (six to 10 inches) of new snow and will continue overnight. Winds are expected to be moderate to strong. On Sunday, clouds with easing flurries may bring 10 to 20 centimetres (four to eight inches) of new snow, for a total of 60 to 90 centimetres (24 to 35 inches) of snow over two days. Moderate winds are anticipated to ease over the day.
Avalanche Canada recommends using sheltered terrain where new snow hasn’t been affected by wind, and to avoid terrain that has freshly wind-loaded features.
Full avalanche details are available at the Avalanche Canada website.
Further weather details are available at the Mountain Weather Forecast.
Travellers should also check the DriveBC website for road conditions, closures, and updates.