Avalanche Advisory Archive 2016 – 2018
|Date Issued:||2017-01-25 06:57:07|
These windslabs have been building over the last several days with considerable to high winds.
In general the storm slab is less than 20cm... but the windslabs are much much deeper in places around the region at upper elevations.
These are getting stiff and probably harder to trigger and yet they are also becoming more dangerous in the form of a hard slab avalanche over a soft slab.
As loading increases due to continued precip and wind both, and temperatures continue to raise slightly, be aware these wind slab avalanches are likely to occur both by human triggers and naturally.
Be aware the lower mountain snowpack is once again quite moisture saturated with meltwater all the way through the snowpack to the ground.
This created poor bonding and increases the ability for wet loose, wet slab and the larger glide avalanches in places.
Be aware that until the snowpack cools again this will remain a concern on steep open areas with few or no anchors.
Be aware of steep unsupported convex rolls and terrain traps that increase your danger.
Be safe out there and have a great day.
The National Weather Service Forecasts-
Today- Rain showers. Highs around 41. Southeast wind 10 to 20 mph. Wind gusts to 30 mph in the morning.
Tonight- Rain showers. Lows around 37. Southeast wind 10 to 20 mph. Wind gusts to 35 mph late.
Thursday- Rain. Highs around 42. Southeast wind 10 to 15 mph... Except south 30 mph with gusts to around 40 mph near downtown juneau and douglas.
Temperatures are quite warm around the region this morning. The Mt Roberts Tram summit is showing 34f. At Eaglecrest we have 36f at the bottom, 33f at Mid Mountain and 32f on top.
We saw moderate precipitation over the last 24 hours with .5\" precip at the tram and .3\" at Eaglecrest. This returned us a net loss to the snowpack overall at our mid mountain elevations.
Yesterday's field work showed us that at summit elevations the snowpack is slightly colder and still holding dryer snow and more volume. Where the Eaglecrest Powder Patch gauge is only snowing 7cm of new snow over the last 5 days received from 20mm of precipitation. Snowpits yesterday showed closer to 20cm of new snow with additional windloading accumulation in places.
Winds have been quite strong around the region over the last 5 days as well with most periods in the 20+mph range and hitting 40+ throughout much of the time. Be aware of windloaded areas with increase danger.
The lower elevations once again are quite moisture saturated with meltwater throughout the pack down to ground level in many places. This raises the chance for wet loose, wet slab, and glide avalanches.
The upper elevation snowpack also hold danger in the form of windslabs and cornice fall danger. Yesterdays pits showed several prominent weak layers with very low test scores. We had CT and ECT failures down to 35cm with scores from 3-13.
The slabs on top of the deeper weak layer are gaining strength but this is a false sense of security that needs to be avoided. The weak layers of cold snow remains a large concern especially as we continue to add load over the next 24+ hours.
With slight warming in the forecast for the next 24 hours up through the point of freezing, precipitation forecasts of .5\" over the next 24 hours and continued considerable windloading avalanche danger remains CONSIDERABLE at this time.
Natural avalanches remain possible and human triggered avalanches are likely in windloaded areas.
Use caution out there is you choose to venture into the backcountry today.
Here is a link to some great avalanche forecasting practice session and training. You could learn a great deal on this site over time.