The National Weather Service Forecasts-

TODAY...SNOW DEVELOPING...MIXING WITH RAIN SOUTH OF TAKU INLET IN THE AFTERNOON. SNOW ACCUMULATION 2 TO 4 INCHES. HIGHS AROUND 32. SOUTHEAST WIND 25 MPH.

TONIGHT...SNOW...EXCEPT RAIN SOUTH OF TAKU INLET IN THE EVENING. SNOW ACCUMULATION 2 TO 5 INCHES. LOWS AROUND 30. SOUTHEAST WIND 10 TO 20 MPH.

THURSDAY...SNOW SHOWERS. SNOW ACCUMULATION 1 TO 3 INCHES. HIGHS AROUND 32. SOUTHEAST WIND 15 TO 25 MPH DECREASING TO 10 TO 15 MPH IN THE AFTERNOON.

In the last 2 weeks we have received about 2' of new snow. Before that time we had rains to summit elevations and very warm temperatures.

This rain event stabilized the lower snowpack quite a bit.

The primary concern today lies in the upper layers in the snowpack and the new load that is coming in today into tomorrow.

Yesterday I dug quite a few snowpits in different areas to better understand the nature of the snowpack that is lying on the stable snow beneath it.

The new snow ranged from 25-110cm in different locations. There has been a great deal of wind effect during the last 2 weeks which has added greatly to spatial variability.

The average depth of the old/new snow interface was at about the 60cm mark(2').

Above this interface we have multiple density changes and weak layers. Where two days ago the powder was cold and fluffy, yesterday it had more density and was more wind affected.

I found everything from perfect fluffy powder to moderate density wind slabs. Yet most of the snow was fairly stable.

To beter understand the nature of this stability I did several snowpit tests in each of my pit locations. I concentrated on shovel shears, compression tests, and extended column tests.

Most locations had fairly similar results. My shovel shears were breaking through multiple layers from 20-35cm on an uneven plane. My compression tests were failing fairly consistantly at about the 41cm mark with quality 1 shears(Q1= flat clean shears)with a score of 12-13. Upon continuing the tests I got a secondary release at 62cm under the degrading old melt freeze crust with a Q1 shear and a score of 20. (tests score from 1-30 w/1=very weak and 30=very strong)

These tests showed us the presence of weak layers in the snowpack at multiple elevations with the ability to tear down into deeper weak layers with additional stress on the snowpack.

Upon performing Extended Column tests in the same locations I found it interesting that I could not get clean ECT failures. Most of the test sites simply collapsed and settled in place and did not fail in fracture or propagation.

This shows us that although there is a weakness in the snowpack layering it is hard to define the nature of its ability to create avalanches.

Spatial variability is quite high. This adds to the multiple variables in the snowpack stability equasion making it harder to say conditions are safe. Be sure to make individual assesments for the areas you choose to ride in. Do not take anything for granted or assume that becuase one slope is stable the others will be also.

As this new snow comes in over the next 24-48 hours temperatures should remain cool. Winds are forecasted at moderate and are currently in the 10-20 knot range. The precip volumes are also moderate.

As this storm comes in avalanche danger will rise slowly. Be aware that avalanche danger is MODERATE at this time.

Human triggered avalanches are possible in areas.

Have a great day and remember the basics. Transceiver, probe, shovel, and partner... dont leave home without them.

Here is an excellent article I wanted to share with you from local avalanche forecaster Ron Simenhois from Couer Alaska and the Kensington Mine. Thank you Ron for your continued contributions to Juneau Avalanche Safety! We are fortunate to have you in our region.

Know the Snow: Simple decision making and stability assessment.

By Ron Simenhois

Whenever I go into the backcountry, I use a holistic approach to evaluate the snowpack. I start to seek clues and insights into the state of the snowpack in the mountains with my morning coffee. I start my day checking recent weather and the forecast on the Internet (my first stop is Juneau?s National Weather Service website: pajk.arh.noaa.gov). On my way to the trailhead, I look around, searching for recent avalanche activity, check-in with friends to find out if they saw any avalanches, and often stop by the ski patrol to ask about results from recent avalanche control work.

As I skin, I pay attention to the way recent winds have redistributed the snow. I look to see if the snow surface is smooth, rough or shiny. Are there shooting cracks in front of my skis?

I listen to the sound of the snow as I travel: is it drummy? Does it make hashing sounds? Or does it collapse underneath me? I notice how much I sink into the snow and more.

To make sure I don?t miss important information, I remind myself of the article ?Obvious Clues? by Ian McCammon (The Avalanche Review, December 2006). The article addresses the question: is there a classic avalanche accident pattern or it is just simple hindsight bias that kicks in? To better understand hindsight bias, think about an accident. Before disaster strikes, all outcomes seem more or less equally probable. But once the couch catches on fire, a buddy falls off the roof or a bar fight breaks out, the signals of impending doom seem obvious and the chain of events leading up the accident seems to have led inescapably to the outcome. This effect, known as the hindsight bias, is especially pronounced when we look at the actions of other people. McCammon examined avalanche accidents, looking for evidence of the well-recognized seven signs of apparent avalanche danger. The seven signs are:

? Considerable (a three on a one-to-five scale) or higher rating in the local avalanche forecast.

? Recent avalanche activity.

? Signs of unstable snow like cracking, collapsing or breaking train in deep snow.

? Playing in an obvious avalanche path.

? Present or recent snow loading from wind, snow, or rain.

? Terrain traps like cliffs, gullies or trees.

? Melting of the snow surface.

McCammon?s results suggest there is a consistent pattern in the majority of avalanche incidents. In fact, in more than half of the accidents McCammon examined, five of the seven obvious signs were present.

My practical experience has shown things start to feel serious when three of the seven clues are present. This is where I usually take a big breath, reassess my goals and evaluate my decisions carefully. When four of the seven clues are present, things start to get tricky; the situation starts to feel ?out there,? margins of safety grow thin and finding a safer route starts to feel like a really good idea. Field experience indicates that when more than four clues are present, even experienced back-country travelers may have a hard time making it back home safely. In hindsight, the presence of four or more clues is precisely the conditions where I have had the majority of my near misses. Sadly, that?s where I have started to convince myself that things aren?t really that bad.

I like the three out of seven clues thresholds; it is a quick and simple tool that relies on basic observations rather than years of experience or detailed knowledge of snow science.

Unfortunately, we cannot forecast avalanches with a simple list of the obvious signs. It is only a reminder that one could be entering a situation similar to other situations where avalanche accidents have happened. Think about it as a well-thought-out checklist used to pack for a long trip ? missing a few items from the list doesn?t mean the trip will fall apart. But if the trip does fall apart, it?s likely because some key items were overlooked.

When touring in the backcountry, I use this as a set point to ?stop and reassess? the situation. Knowing when to stop and reassess is half the battle.