Avalanche Advisory Archive 2016 – 2018

Date Issued:2017-01-15 07:47:46
Danger:3
Primary Trend:2
Primary Probability:7
Primary Likelihood:2
Primary Size:2
Primary Description:

With 4+\" of precipitation in the last 3 days and another 2+\" in the forecast for the next 36 hours at mostly above freezing temps avalanche danger will remain considerable.

Watch the moisture penetration through thee layers... as the moisture penetrates deeper and deeper we again question the stability of previously stable dormant layers.

Use a little extra cation today due to all the recent loading, warming, and rain...

Secondary Trend:2
Secondary Probability:3
Secondary Likelihood:2
Secondary Size:2
Secondary Description:

Once again we received 18cm of snow during 4\" of rain with 50-70mph winds. This built large windslabs in starting zones.

With increased wind, and precip today these windslabs remain in question. These areas have increased load and stress... and may be closer to a state of failure.

Use extra caution in these deeper windloaded areas.

Discussion:

The National Weather Service Forecasts-

Today- Becoming very windy. Numerous rain showers early in the morning...then rain. Highs around 42. East wind 10 to 20 mph increasing to southeast 30 to 40 mph with gusts to around 50 mph late in the afternoon.

Tonight- Very windy. Rain...heavy at times. Lows 33 to 39. Southeast wind 30 to 40 mph with gusts to around 50 mph decreasing to 15 to 25 mph with gusts to around 40 mph late.

Martin Luther King Jr Day- Rain...heavy at times. Highs 37 to 43. Southeast wind 10 to 20 mph...except south 35 mph with gusts to around 50 mph near downtown juneau and douglas.

The Eaglecrest gauges have seen 4\" of rain over the last 4 days that translated to only about 7\" of snow. This is incredibly wet dense snow as well as a not moisture saturated snowpack.

Temperatures remain warm over the region. The Mt Roberts Tram hovered around 1c yesterday while Eaglecrest was slightly cooler at mid mountain right at 32 for most of the day.

Winds were VERY high creating great windloading at upper elevations during this storm event. This deposited additional load in starting zones and increased stress.

Temperatures are forecast to remain warm today at above freezing temps to our mountain summits. This continues to weaken the bonds in the snowpack and brings previous instabilities into question.

Look to see how the deeper wind slabs are stabilizing or getting weaker over time. Look for full depth penetration and ground saturation. This could lead to full depth avalanches in areas with no anchors to hold snow in place. Danger levels remain CONSIDERABLE today.

Natural avalanches are possible in places and human triggered avalanches remain more likely in steep unanchored convex slopes where terrain increases stress due to creep, glide, and settlement.

Todays forecast calls for high winds with mostly rain. Temps to cool perhaps slightly over the next 24 hours.

Todays forecast calls for moderate rain amounts. Tomorrows forecast calls for HIGH precipitation volumes which may increase danger in the region.

Today is all about temperature positive powder... its deep... and its wet... but its soft and fun... Use a little extra caution today in the areas you choose to recreate.

Tip:

A special THANK YOU to the Juneau Snowmobile Club, Juneau Mountain Rescue, and SEADOGS for coming out yesterday to the Juneau Multi-agency Search and Rescue Drill.

Its great to see so many caring people training and polishing their skills to support the community for a worst case scenario.

THANK YOU FOR CONTRIBUTING TO OUR COMMUNITY

Forecaster:Tom Mattice