Avalanche Forecast

Issued: Mar 6th, 2019 4:26PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Wind Slabs and Persistent Slabs.

kdevine, Avalanche Canada

Cariboos.

Convective snow showers may bring higher than forecast snowfall amounts to some areas. In areas that receive 20 cm or more, consider the danger rating to be MODERATE at all elevation bands.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

Convective snow showers on Thursday could mean that some areas receive higher than forecast snowfall amounts.WEDNESDAY NIGHT - Mainly cloudy with flurries, up to 5 cm / southeast winds 10-20 km/h / alpine low temperature near -8THURSDAY - Mainly cloudy with flurries, 5 cm. / southwest winds 25-40 km/h / alpine high temperature near -8FRIDAY - Mainly cloudy with flurries, 3-5 cm / west winds 10-30 km/h / alpine high temperature near -10SATURDAY - A mix of sun and cloud / west winds, 15-30 km/h / alpine high temperature near -9

Avalanche Summary

No new avalanches have been reported in the region over the past few days, but observations in neighbouring regions have shown regular, generally small (size 1) wind slabs reacting to skier traffic at upper elevations. Avalanche activity on the mid January persistent weak layer has tapered off, however test results still suggest that this layer could be triggered by humans in specific locations. When persistent weak layers stop producing regular avalanches, they can become very difficult to manage. This weak layer has become a low likelihood/high consequence avalanche problem. Check out a recent MIN report from Allen Creek here that illustrates this.

Snowpack Summary

5-10 cm of snow is expected to fall overnight Wednesday and through Thursday. Some convective snow showers could mean that some areas see up to 20 cm.The new snow will sit mainly on wind slabs and facets (sugary snow) and a crust on sun exposed slopes. The wind slabs are also sitting on facets and they may continue to be reactive. At lower elevations, a weak layer buried in mid January can be found approximately 50-60 cm deep. This layer consists of surface hoar (feathery crystals) and facets, and may be combined with a crust on south facing slopes. This layer has been most reactive at treeline and below treeline. The lower snowpack is generally considered to be strong, except for shallow, rocky areas where cold temperatures continue to facet (weaken) the snowpack.

Problems

Wind Slabs

Wind slabs can be found on all aspects and may continue to be reactive due to the weak, faceted snow they sit above. They may become difficult to detect as they get buried by the new snow.

Increase caution around wind loaded pockets near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 1.5

Persistent Slabs

50-60 cm of snow sits above a persistent weak layer of surface hoar buried in mid-January. This layer has evolved into a lower likelihood/high consequence avalanche problem.

Maintain diligent group management around open and/or sparsely treed slopes at treeline and below.Exercise increased caution around low elevation cut-blocks where this layer has been well preserved.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely

Expected Size

1 - 2

Valid until: Mar 7th, 2019 2:00PM