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 Sunday, March 26, 2017

Expires 7:00am on Monday, March 27, 2017
Issued by Tom Mattice


Avalanche Danger Level 2

Click here for danger definitions



Today's Discussion

The National Weather Service Forecasts-

Today- Cloudy. Isolated rain and snow showers early in the morning. Highs around 43. North wind 10 to 15 mph.

Tonight- Rain likely, mixing with snow late. Little to no snow accumulation. Snow level 500 feet. Lows around 34. Northeast wind 10 mph in the evening becoming light and variable.

Monday- Snow in the morning then rain. Snow accumulation to 1 inch. Snow level increasing to 1100 feet in the afternoon. Highs around 43. Southeast wind 10 to 15 mph.

Good morning. Winds are fairly calm this am. Eaglecrest is showing 6-8mph and its blowing 10-12 at the Tram.

Yesterday winds were calm as well.

Eaglecrest is showing 28f at the base and 25f on summit this am. Mt Roberts is 29f.

Mt Roberts picked up 5cm of snow (2" ) While Douglas Island got closer to 12cm(5").

Winds should remain calm today. We are calling for clouds and snow later in the day. Danger is Low for natural avalanches and yet we have a persistent weak layer remain in the region in places that can still be human triggered.

With human triggers possible avalanche danger is MODERATE today. Natural avalanches not likely yet human triggered slides possible in places. We could see small avalanches in specific areas in the new snow; or large avalanches in isolated areas down on the deeper persistent weak layer.

Use caution in areas with extreme exposure.


Primary Avalanche Problem


PERSISTENT SLAB
Persistent Slab

AVALANCHE PROBLEM
Avalanche Size Level = LargeAvalanche Probability = PossibleAvalanche Danger Trend Next 24 Hours = Stable

Description

The persistent slab problem remains in the region. Look to see if its still present where you ride? Have you done a pit recently on your favorite slope? did your slope slide last week? maybe the new snow is more stable there?

This new snow may keep the persistent weak layer easier to trigger as well. Use caution

Secondary Avalanche Problem


LOOSE WET
Loose Wet

AVALANCHE PROBLEM
Avalanche Size Level = SmallAvalanche Probability = PossibleAvalanche Danger Trend Next 24 Hours = Stable

Description

Its supposed to cloud up today. Should that occur this will ot become an issue. Yet with temps near freezing at the Tram it wont take much direct sunlight to weaken this snow.

Watch the sun today... if it stays out be aware of danger increasing on south to southwest facing slopes later in the day. Avoid south to southwest facing slopes during the heat of the day into early evening.

If we see much clouding this will not become an issue.



Today's Avalanche Tip

Probability Vs Consequence.

The current danger is not highly probable... yet the slab releasing in the region has been from 50-90cm. It is becoming more of a hard slab. So although probability is low consequence is High.

Here is an interesting article that may tell you more.

http://monosar.org/safety_article_avalanche_risk_assessment.html

This Advisory applies to the Mt. Juneau Avalanche Zones



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