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 Saturday, February 6, 2016

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


Avalanche Danger Level 2

Click here for danger definitions

Avalanche Trend Level 2Avalanche Size Level 2

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STORM SLAB

AVALANCHE PROBLEM
Avalanche Likelihood 3


Today's Discussion

The National Weather Service Forecasts-

TODAY...SNOW AND RAIN SHOWERS EARLY IN THE MORNING...THEN CHANCE OF RAIN SHOWERS AND SNOW SHOWERS IN THE AFTERNOON. SNOW
ACCUMULATION UP TO 1 INCH...MAINLY WITHIN MENDENHALL VALLEY.
HIGHS AROUND 39. SOUTH WIND 10 TO 15 MPH.

TONIGHT...MOSTLY CLOUDY. SLIGHT CHANCE OF RAIN IN THE EVENING.
CHANCE OF SNOW. LOWS AROUND 30. EAST WIND 25 MPH.

SUNDAY...SNOW...MIXED WITH RAIN IN THE AFTERNOON. SNOW
ACCUMULATION 1 TO 3 INCHES. HIGHS AROUND 37. EAST WIND 10 TO 20
MPH.

SUNDAY NIGHT...RAIN LIKELY. LOWS AROUND 34. SOUTHEAST WIND
15 MPH

Bottom Line: Avalanche Danger is MODERATE still today. Human triggered avalanches possible. Natural Avalanches Unlikely.

The concern comes from the bond between the new snow that started 3 days ago and the old snow. It was not bonding well at all at the beginning of the storm. Human triggered avalanches were wide spread two days ago at mid to upper elevations 2000-2600ft.

We have received more than a foot of snow over the last 3 days at upper elevations. With moderate to considerable windloading at times. The storm started slow with high winds and light precipitation creating shallow windslabs on lee N-W slopes. As the precip increased the winds slowed and moved a little to the west. So we created a shallow wind slab on certain faces then followed up with a good dump of snow that was not bonding well on all faces. Danger exists on all aspects but is increased on W-N aspects from the first days windloading and the winds again this morning.

The last two days should have given this deeper weak layer time to settle out and bond a little better. But be careful and check for weakness in the areas you choose to play. How well is this snow bonding now?

Temperatures remained near freezing for the last 24 hours which helps in the settlement and bonding process. The Tram was 31f yesterday morning and has dropped to 30f today. Eaglecrest is currently 32f at the base and 29f at mid mountain.

Precipitation was light over the last 24 hours with 6mm of precipitation at the tram summit depositing 6cm of new light snow. Eaglecrest received a little more with 9mm of precip and 7cm of new snow. This will add stress to the previous weak layer but not a great deal. This new snow should bond fairly well to the old snow.

Winds are currently an issue with moderate windloading out of the SE. The tram is showing 10-15 gusting 20mph and Eaglecrest is a bit higher with 15-20mph winds gusting 25mph. This is continually adding stress to the previously windloaded pockets on the N-W faces. Be aware that Human Triggered avalanches remain possible in these areas.

Forecasts for today are light precipitation, light to moderate winds and continued cool temperatures. Stability should continue to increase over the next 24 hours.

Be safe out there and enjoy a great day. Use a little extra caution in the Backcountry today. Have fun!

Today's Avalanche Tip

A tragedy yesterday in Montana. Anchorage resident passes away in avalanche. My thoughts go out to his family and friends.

http://m.nbcmontana.com/news/MSU-student-dies-in-backcountry-ski-accident/37841530

There was also a man killed in an avalanche in Colorado while snowbiking.

http://www.denverpost.com/news/ci_29482358/man-ski-bike-buried-killed-by-cottonwood-pass

The terribly sad part of both of these incidents is that these people chose to head into the mountains ALONE. When accidents happen, and they do, you have no ability to recover.

Please ride with a partner. Both of you must be equipped with an Avalanche Transceiver, Probe, and Shovel.

Please practice together and have a plan. Spot each other through avalanche prone areas one at a time. Stay safe out there!!!

This Advisory applies to the Mt. Juneau Avalanche Zones



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