Avalanche Advisory Archive 2016 – 2018

Date Issued:2017-03-29 08:28:12
Danger:3
Primary Trend:1
Primary Probability:6
Primary Likelihood:3
Primary Size:1
Primary Description:

We picked up several inches of snow a day for the last few days at upper elevations.

Daily temperature fluctuations are now taking the mid day high above freezing most of the way up the mountain. When this occurs we start to peel the snow layers off in wet slides like the layers of an onion...

With temps increasing today and continued precip look to see small wet slides on steep faces as snow cleans off of trees and rocks.

Be aware these small wet loose slides add a lot of stress to the deeper weak layers in place. Be cautious recognizing one small slide could be the trigger for a much deeper bigger event.

Secondary Trend:2
Secondary Probability:4
Secondary Likelihood:2
Secondary Size:2
Secondary Description:

The persistent weak layer remains in the region.

From 50-100+cm deep in places. Look for weak layers in your field tests.

It has been gaining some strength over the last week with the warm temps and daily fluctuations going over freezing yet recognize danger remains in isolated locations.

Discussion:

The National Weather Service Forecasts-

Today- Widespread rain showers. Snow level 1000 feet early in the morning. Highs around 45. South wind 10 to 15 mph.

Tonight- Numerous rain showers. Scattered snow showers late. Little or no snow accumulation. Snow level 1400 feet in the evening. Lows around 33. South wind 10 mph.

Thursday- Mostly cloudy. Scattered snow showers in the morning. Scattered rain showers in the afternoon. Highs around 42. Southeast wind 10 mph.

Temperatures remain warm around the region this morning. The Tram has only been below freezing for 3 hours since Sunday morning. Currently the tram is 33f. Eaglecrest is 34f at the base. 31f at mid mountain and 30f on top. Just cold enough to keep the snowpack locked up and somewhat stable.

Winds were moderate over the last 24 hours with 10-20mph south winds.

We picked up around 8mm of precip in the region. This came mostly as rain down low. We picked up 5cm at Eaglecrest and 2cm at the tram of new snow but the snowpack lost snow in total due to settling.

With todays forecast calling for continued light rains and warming we may see small wet loose avalanches. This rapid settling, warmth and precip adds stress to the persistent weak layer already in place as well. Although not likely we could see natural activity on this deeper layer as well. Especially in places that get loose wet avalanches adding tot he trigger.

With natural avalanches and human triggered avalanches both possible avalanche danger is moderate to CONSIDERABLE.

Look for small wet slides raising in elevation as the day warms... The more warming we see... and the more precipitation we see... the more activity we should see... yet all activity should be limited in size unless you find that deeper weak layer becoming reactive once again.

Tip:

Here is a link to an interesting article by Avalanche Canada.

http://www.avalanche.ca/blogs/low-btl-danger-full-path-avalanches

Forecaster:Tom Mattice