Avalanche Advisory Archive 2016 – 2018

Date Issued:2017-03-21 06:58:24
Primary Trend:2
Primary Probability:4
Primary Likelihood:3
Primary Size:2
Primary Description:

We saw two big storms in the last month during periods of great cold which left multiple weak layers in place. This weakness is fairly widespread.

We have seen avalanche activity from 30-75+ cm in depth.

These are propagating widely and through the woods even.

Use extreme caution on slopes greater than 35degrees. It wont take much in terms of slope angle or terrain shape to get things moving...

Remember to avoid steep convex rollovers. Avoid terrain traps at all cost right now. These slides are large in size.

Secondary Trend:1
Secondary Probability:6
Secondary Likelihood:2
Secondary Size:2
Secondary Description:

With temperatures going above freezing today in our lower starting zones we may see small wet loose avalanches being started from snow falling off of trees and rocks.

In steeper longer areas these could entrain quite a bit of snow.

These could also be the trigger for bigger avalanches...

If we get much direct sunlight today this weakness will increase during the mid to later part of the day as well.

Keep an eye on the snowpack. These should be fairly easy to avoid unless you find that one small slide that becomes the trigger for the deeper persistent weak layer in place.


The National Weather Service Forecasts-

Today- Mostly cloudy. Patchy freezing fog early in the morning. Highs around 41. Light winds becoming north 10 mph.

Tonight- Mostly cloudy. Lows around 28. Northeast wind 10 to 15 mph.

Wednesday- Rain likely in the afternoon. Highs around 40. northeast wind 10 to 20 mph.

Good Morning Juneau... I hope you have been paying attention to the avalanche conditions out there. Although urban danger is relatively low... we have a persistent weak layer, or several is it may be keeping danger lingering at CONSIDERABLE.

Winds have died down overnight and are mild this am. Eaglecrest is showing 8-10 out of the North and the tram is even less at 6-8mph. Yesterday we did see a long period of 20-40mph winds from the SE. Its important to remember we have seen winds from the S-SE and the N over the last week loading multiple aspects.

We received only 2mm of precip yesterday with around an inch of snow.

Temperatures warmed up yesterday to above the point of freezing at tram summit elevations helping with the consolidation and bonding process.

The forecast for today calls for mild winds and diurnal warming again to above the point of freezing. This willhelp with stability over time... but not so much in the short run. Danger levels will actually increase during the heat of the day. Especially if we see much direct sunlight today.

Be aware we have a deep underlying persistent weak layer which has continued to be very trigger sensitive. We have seen a great deal of human avalanche activity on these layers in the last 5 days. This weakness appears to be fairly widespread. It will stay with us for some time... possibly until we get enough rain or spring warming to create an isothermal snowpack. The bottom line is things will be touchy for a while... Now is a good time to use best practices in terrain management. Avoid slopes in the upper 30's and low 40's for slope angle. We have even been seeing avalanche reports coming from the thick trees.

With not much wind today and no precip natural avalanches are not likely... yet with warming to above the point of freezing and the possibility of sunlight we may see wet loose avalanches forming later in the day. But remember with human triggered avalanches remaining likely avalanche danger remains CONSIDERABLE.

Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential. Be increasingly cautious in or under steeper terrain and in avalanche zones.

Please once again avoid the flume trail today... especially during the mid to later part of the day.


I am taking this note from Alaska Avalanche Specialists Bill Glude.... He posted this on facebook and it is a great reminder to us all.

Note that 1. you need to keep off, and out from under, any slope with an angle in the upper 30?s or higher when we have this kind of sensitive, persistent instability and

2. not only is it a myth that trees are \"safe\", but slides are quite frequent in the trees, and you are five times more likely to die of trauma in a slide in the trees than on an open slope!

Take care out there!

Forecaster:Tom Mattice