City and Borough of Juneau
155 S. Seward Street
Juneau, Alaska 99801
tel. 907-586-5240
fax 907-586-5385
http://www.juneau.org

Urban Avalanche Advisory

Current Advisory as of Monday, February 8, 2016

Expires 7:00am on Tuesday, February 9, 2016
Issued by Tom Mattice


Avalanche Danger Level 3

Click here for danger definitions

Avalanche Trend Level 4Avalanche Size Level 2

Click here for size definitions

WET SLAB

AVALANCHE PROBLEM
Avalanche Likelihood 4


Today's Discussion

The National Weather Service Forecasts-

TODAY...PATCHY FOG. CHANCE OF RAIN EARLY IN THE MORNING... THEN
RAIN ... HEAVY AT TIMES IN THE AFTERNOON. HIGHS AROUND 40.
SOUTHEAST WIND 10 TO 15 MPH.

TONIGHT...RAIN. LOWS AROUND 37. SOUTHEAST WIND 10 TO 15 MPH.

TUESDAY...RAIN LIKELY...MAINLY IN THE MORNING. HIGHS AROUND 43. EAST WIND 10 MPH...EXCEPT DOWNTOWN JUNEAU AND DOUGLAS. EAST WIND 10 MPH BECOMING NORTHEAST WIND 10 TO 20 MPH WITH GUSTS TO 35 MPH.

At Mt Roberts Tram Summit Weather Station we have received 32mm of precipitation since the morning of the 2nd. This left us about 25cm of new snow at that elevation. A little more snow fell near summit. This layer showed some weakness over the last few days with skier triggered avalanches occurring near the base of this layer. At the beginning of the event it was not bonding well and sliding off of the old snow surface. On Saturday the bond had healed but a weak layer due to a density change was present just above it. I was able to skier trigger several small slides at about 30cm of depth.

Temperatures yesterday morning were 27f at Tram Summit and also 27f at the Eaglecrest weather station. This morning those temperatures have climbed several degrees. The tram is 36f while Eaglecrest remains 34f at mid mountain and 32f at the top.

We received 2.5mm of precip at the Tram summit leaving 5cm of new snow at the beginning of the event that ended as 3cm. Eaglecrest received 4mm of precip yet only 1cm of snow with a net loss of 1cm of snow overall.

Winds remain light this morning with 5-10mph NE winds. The tram is a little higher at 8-12.

The forecast for today calls for moderate precipitation early in the day increasing to considerable precip overnight with .85" of precip in a 12 hour period. Temperatures will continue to warm over the next 24 hours with tomorrow being 2+f warmer than today.

This will place considerable stress on the weak layer already in place.

THE BOTTOM LINE: Avalanche Danger is CONSIDERABLE today.

Natural avalanches possible; human-triggered avalanches likely.

This becomes especially true as tonight's precipitation rate increases during these warm temperatures.

Slides in the urban environment are not forecast to be very large.

Use extra caution in the backcountry until the temps cool back down again after this tropical punch over the next few days.

Today's Avalanche Tip

Here is a link to a great interactive avalanche awareness safety presentation.

http://avalanche.org/tutorial/tutorial.html

Eaglecrest is hosting an Backcountry Safety Awareness and Companion Rescue Course Saturday March 5th from 8:30am-3:30pm.

This course is free and sponsored by the Department of Public Safety.

During this day long course you will learn about avalanche terrain, weather, and stability assessment tests. You will also learn about Avalanche Rescue as well as transceiver, probe and shovel use.

Please share this offering with your friends. Lets all do out part to maintain a safe backcountry community.

For more information or to sign up please email Tom.Mattice@juneau.org

This Advisory applies to the Mt. Juneau Avalanche Zones



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