Avalanche Forecast Northwest Coastal

Date Issued: Valid Until:

Avalanche Canada ghelgeson, Avalanche Canada

Avalanche Forecast

Mon Apr. 15th ยท 3:27PM

Alpine

Danger Ratings Considerable

Treeline

Danger Ratings Considerable

Below Treeline

Danger Ratings Low
Storm Slabs Storm Slabs

Alpine

Danger Ratings High

Treeline

Danger Ratings Considerable

Below Treeline

Danger Ratings Low

Alpine

Danger Ratings Considerable

Treeline

Danger Ratings Moderate

Below Treeline

Danger Ratings Low
Strong southwest flow should deliver significant snow and wind beginning Monday night. If more than 30 cm of new snow falls then danger ratings should all be bumped up one level, so Considerable becomes High.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain on Tuesday

Weather Forecast

A fairly juicy pattern is setting up that should deliver significant snow and wind to the Coast beginning Monday night carrying on through at least Friday. These systems are pretty convective which makes it difficult to pin down accurate snowfall amounts, but it looks like winter is coming, back, at least to the alpine over the next few days.MONDAY NIGHT: Freezing level rising to around 1000 m, moderate to strong southwest wind, trace to 10 cm of snow possible. TUESDAY: Overcast, freezing level around 1000 m, strong southwest wind, 10 to 25 cm of snow possible, with another 10 to 20 cm possible Tuesday night.WEDNESDAY: Overcast, freezing level around 1100 m, moderate to strong southwest wind, 2 to 6 cm of snow possible during the day with 5 to 15 cm possible Wednesday night.THURSDAY: Broken cloud cover, freezing level around 1200 m, moderate to strong southwest wind, 1 to 5 cm of snow possible.

Avalanche Summary

Ne new avalanche activity to report from Saturday or Sunday.We received a great MIN report on Friday. It details a few avalanche occurrences including a size 3 on an east facing slope and lots of loose wet activity from steep terrain.

Snowpack Summary

The region received 5 to 20 cm of snow Saturday into Saturday night. There is now about 20 cm of dry snow on high elevation north facing slopes and a 5 to 10 cm melt freeze crust on all other aspects. As we enter into mid-April we're dealing with a classic warm snowpack. At and below treeline the snowpack is becoming isothermal. We're tracking the April 4th crust which is down 20 to 80 cm below the surface on high elevation north facing slopes. Surface hoar and facets have been observed on this crust and it continues to produce sudden planar results in snowpack tests. We have not heard of any activity on this interface recently, but this week's cycle of storms have potential to activate it. Digging deeper, north facing alpine terrain also has a layer of facets down approximately 100 cm below the surface which are thought to be dormant at this time.

Problems

Storm Slabs

Storm Slabs

We're expecting up to 10 cm overnight and as much as 20 cm Tuesday. A natural avalanche cycle at upper elevations is possible. Be prepared for conditions to steadily deteriorate throughout the day and make sure you've got a clear and safe route home.

Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5