Avalanche Advisory Archive 2016 – 2018

Date Issued:2017-03-28 06:58:53
Primary Trend:1
Primary Probability:6
Primary Likelihood:2
Primary Size:1
Primary Description:

We picked up 15-17mm of precip yesterday with only 2cm snow at mid mountain. This could be quite a bit more at upper elevations... yet it is very moisture saturated.

This will easily trigger wet loose avalanches as we have mid day warming again today. Snow will be cleaning off of steep faces, trees, and rocks.

This has the ability to entrain a fair amount of snow and even the ability to trigger the deeper weak layers in place.

With warm temps and super wet snow we may see some activity. Yet temps are not going that high and we are drying out a little as well. This should limit activity.

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

Although healing this weak layer remains present throughout the region. Some places more so than others. Have you dug and looked in your favorite riding place?

This is a low probability high consequence layer now being from 50-100cm below a hard slab.

Use caution in steep open faces. This precip yesterday and spring warming are adding stress to the pack. Although healing this is also placing stress on the snowpack.


The National Weather Service Forecasts-

Today- Mostly cloudy. Patchy fog early in the morning. Scattered rain showers. Highs around 43. Light winds.

Tonight- Numerous rain showers, then scattered snow showers late. Snow accumulation to 1 inch. Snow level 800 feet late. Lows 30 to 36. Light winds.

Wednesday- Patchy fog in the morning. Numerous snow showers in the morning. Numerous rain showers. Little or no snow accumulation. Snow level 1100 feet. Highs around 42. Light winds.

Temperatures around the region were warm yesterday with both the tram and Eaglecrest mid mountain climbing above freezing for some time. Eaglecrest had a high of 34f at mid mountain and the tram saw 37f. Currently its 33f at the Eaglecrest lodge, 31f mid mountain and 30f on top. The tram remains just above freezing at 32+f.

Winds were moderate yesterday around the region with the tram blowing 10-20 and Eaglecrest at 15-25 out of the SE....

We received a fair amount of precipitation yesterday. Eaglecrest picked up 15mm (.6\") and Mt Roberts got slightly more at 17mm. All of that did not yield much in the way of new snow for our mid mountain weather stations with each only picking up a few cm. You can assume those volumes are much greater at upper elevations.

What this translates to is that we have a snowpack that is warming and above freezing to mid mountain... Todays warming will increase freezing levels a little once again.

This combination of warming and the 1/2+\" of precipitation will rapidly erode the bonds in the snowpack. It also places a great deal of stress on previous weak layers deeper in the pack. Also consider you had a driving wind adding to the warming equation.

The bottom line for today is with a little new snow, and continued warming to above freezing... we may see wet loose avalanches occurring naturally. These would be primarily in the new snow layers from the last few days.

With temps continuing to climb again today and the increased stress on the slab we could see natural avalanches down to the deeper persistent weak layer as well.

These could occur from a small wet loose avalanche creating enough stress to trigger the deeper slide or naturally as the slab fails with the increased stress and eroding bonds.

With both Natural and Human Triggered avalanches possible today avalanche danger is CONSIDERABLE.

Precip volumes are light today which should help to minimize activity. Just be aware that wet loose avalanches will be easily triggered in places with new snow.

Also be aware that although healing the deeper instability is still somewhat present in the region.


Here is a link to a blow from the Northwest Weather and Avalanche Center.

Ruby Mountain: Low Probability-High?Consequence

Forecaster:Tom Mattice