Avalanche Advisory Archive Pre-2016

Date Issued:2012-01-13
Danger:2
Trend:2
Probability:3
Size:3
Problem:0
Discussion:

The National Weather Service Forecasts-

TODAY...SNOW SHOWERS. SNOW ACCUMULATION 1 TO 2 INCHES.
TEMPERATURES STEADY AROUND 32. SOUTHEAST WIND 10 TO 15 MPH SHIFTING TO THE EAST IN THE AFTERNOON.

TONIGHT...DECREASING CLOUDS. SCATTERED SNOW SHOWERS IN THE
EVENING. LOWS AROUND 21...EXCEPT AROUND 15 IN WIND SHELTERED AREAS. NORTHEAST WIND 10 MPH INCREASING TO 15 TO 25 WITH GUSTS TO 35 MPH NEAR DOWNTOWN JUNEAU AND DOUGLAS LATE.

SATURDAY...PARTLY CLOUDY IN THE MORNING THEN BECOMING MOSTLY

SUNNY. LOCALLY WINDY...COLDER. HIGHS AROUND 23. NORTHEAST WIND 15 TO 25 MPH INCREASING TO 35 MPH WITH GUSTS TO AROUND 45 MPH IN THE AFTERNOON. STRONGEST WIND NEAR INTERIOR PASSES...DOWNTOWN JUNEAU AND DOUGLAS.

The last few days we had quite a storm move through...

Over the last 66 hours we received 96mm of precipitation (nearly 4\") which left nearly 2' of new snow at the Mt Roberts Tram Summit elevation. At the Eaglecrest UAS mid mountain site that was closer to 45cm (18\"). Temperatures rose throughout most of the storm... 7 degrees in the first 24 hours then another 3 in the next 24 hours. Yesterday those mid mountain temperatures were very close to freezing otherwise our snow depth would have been much greater. But recognize that closer to summit elevations we received additional snow do to colder temperatures.

Winds were quite strong during this entire event. ranging from 25-70mph in the first 24 hours, dropping of to 25-45 over the next 24 hours. Yesterday we saw winds pick up to 25-45 with a few hours of winds gusting to 80mph! This created a lot of scouring in places and placed tremendous load in other places.

Yesterday afternoon the winds slowed down and the precip started to slow. Yesterday Evening winds died off more down to 10-25mph and the precip quit altogether. Since that time the temperatures have started to fall. They dropped by about 6degrees overnight starting to lock up the lower snowpack that was quite wet during the event. But the upper mountain areas will still have quite a bit of new snow.

There is great spatial variability. The snowpack has an interesting sandwich if layers. In some places more stable than in others.

Yesterday lots of avalanche activity was witnessed. Human triggered avalanches were widespread. Cornices were quite weak. When those cornices fell the too started avalanches. These avalanches were mostly from 4-12\" yet much larger avalanches occured in places. They were propagating widely as well, often several hundred feet wide.

Natural avalanches were also sighted in the region. Thane road had a very small natural avalanche. Probably from a lower starting zone caused by the warm temps and rains. But much of the upper snowpack remains and is still probably quite sensative. Up near Eaglecrest on Douglas Island large natural avalanches were also reported. One report came in of an avalanche that was several hundred feet wide and perhaps as deep as 3' bring down tons of snow and creating a large powder cloud.

Today things will remain sensative in areas. Winds have shifted direction placing windload in new locations. We may see a bit more new snow. But for the most part the trigger for these natural avalanches is being slowly removed.

Human triggered avalanches remain possible in areas.

Avalanche Danger is Moderate at this time.

Natural avalanches unlikely, potentially destructive avalanches unlikely to come near or reach developed areas.

Human triggered avalanches possible.

Over the next 24 hours danger will continue to decrease yet be aware in places human triggered avalanches will remain possible for several days. Especially with larger triggers like multiple people on a slope... or by snowmobiles.

Use caution in the mountains over the next few days. Be conservative. Limit your exposure. Stick to low angle slopes. Avoid terrain traps, cliffs and unsupported convex slopes.

Time is our friend. The patient man enjoys powder for a lifetime... the impatient man often finds himself in avalanches sooner... than later...

Have a great day everyone. But remember... You need to do everything you can today to stay safe. Dont head into the backcountry without your Avalanche Transceiver, Probe, and Shovel. As well as having a well trained partner who is not pushing you to do things you shouldnt do.

Remember if you choose to play in the mountains today...

LCES-
Place a LOOKOUT as you ski slopes one at a time.
Maintain COMMUNICATION with your partners.
Identify your ESCAPE ROUTES before entering avalanche terrain.
Identify your areas of SAFETY as you ski one at a time from areas of safety to areas of safety... with your lookout spotting you...

HAVE A GREAT DAY!

Tip:

AVALANCHE SAFETY CHECK LIST

BEFORE YOU LEAVE
? Expand your knowledge - take an avalanche awareness class.
? Avalanche beacons, probes & shovels? Know how to use them & practice.
? Check weather / avalanche forecast / local authorities.
? Develop broad mental image of the snowpack and danger you expect.
? Be sure your planned route is suitable for current and forecast conditions.
? Choose competent, compatible partners with similar ability, experience, goals.
? Have several alternative objectives to provide other options for success.
? Leave trip itinerary with family or friend.

IN THE AREA-

Human Factors - Are there issues that overshadow wise decisions?
? Trip Goals: Is a single objective (a summit, a slope) blinding you?
? Feeling too complacent, too familiar, invincible? Watch it!
? More people does not mean safer snow - avoid herd mentality.
? Objective not subjective decisions - don?t base decisions on emotion.
? Are your sport skills outpacing your avalanche skills?

Terrain - Is it suitable for avalanches?
? Slope Angle - Measure it! (30-45 degrees are most common)
? Slope Aspect - Leeward? Wind-loaded? Shaded? Sun-exposed?
? Slope Shape - Convex rolls? Open? Bowl? Gully? Corniced?
? Slope Anchors - Vegetation, Rock outcrops, Benches: Are they anchors or weak points?
? What are the consequences if a slide releases?
? Terrain Traps - Narrow gullies, cliffs, crevasses, trees, rocks, creeks, lakes.

Snowpack - Might it slide? Is it unstable?
Obvious Signs of Instability
? Recent avalanches on similar slopes.
? ?Whumphing? sounds or shooting cracks.
? Consistent ?Very Easy? or ?Easy? failures upon testing.
? HIGH or EXTREME Avalanche Forecast Danger Level.

Other Clues of Instability
? Fresh snow in the past 24 hours.
? Sudden temperature rise or first sunshine on new snow.
? Consistent ?Easy? or ?Moderate? failures upon testing.
? CONSIDERABLE Avalanche Forecast Danger Level.
? Moderate or low danger do not mean NO DANGER.

Weather -
Has it, is it, or will it contribute to instability?
? Precipitation - Type, amount, intensity, duration.
? Wind - Windblown snow loading lee slopes, further stressing snowpack?
? Temperature - Rising temps or sun causing loss of snow strength?
- Prolonged cold temps causing faceting?

Trends in weather are most important; be aware of potential changes with elevation.

TRAVEL -
? Avalanche beacon check at trailhead.
? Look at Terrain, Weather and Snowpack clues - speak up!
? Stay on ridge lines / flanks of open slopes.
? One person at a time crosses suspect slopes - cross high.
? Watch those crossing suspect slopes.
? Follow using the same track; move quickly between safe areas.
? Be ready to ditch gear that inhibits swimming motions: No pole straps or leashes; use releasable bindings.
? Continually look for escape routes - what if the slope releases?
? Choose safe rest areas & campsites - check for hidden tracks & runout zones -
consult map.
? When descending, always stop off to the side of any slope.
? Maintain situational awareness and Reassess continually.

IF CAUGHT -
? Call out!
? Attempt to escape toward flanks (sides).
? Ditch awkward gear.
? FIGHT, swim, grab a tree or rock, self-arrest.
? Keep mouth shut.
? When slowing, make strong thrust toward surface.
? Push one hand toward surface.
? Make air pocket in front of face with other hand.
? Try to dig yourself out.
? Attempt to remain calm.

RESCUE -
? Organize, appoint leader, avalanche lookout, question eyewitnesses (plan beforehand).
? Note who is missing.
? Assess further danger.
? Identify escape routes.
? All beacons to ?receive? mode.
? Establish and mark victim(s) last seen area(s).
? Search for surface clues - check them, then leave them in place.
? Focus search on major deposits and likely catchment areas below last seen area(s), around trees, rocks, bends in path, etc.
? Beacon Search What Who
Phase 1 obtain signal everyone
Phase 2 home in on signal everyone getting signal
Phase 3 pinpoint signal one searcher (others probe and dig)
? Probe for victim until strike is made.
? Manage digging so as not to re-shovel.
? Care for victim - First Aid ABC?s - keep victim warm.
? All beacons back to ?transmit? mode.
? Don?t contaminate site with your equipment.