The National Weather Service Forecasts-

TODAY...SNOW SHOWERS. SNOW ACCUMULATION TO 2 INCHES. HIGHS AROUND 33. EAST WIND 10 MPH.

TONIGHT...DECREASING CLOUDS. COLDER. SCATTERED SNOW SHOWERS IN THE EVENING. LOWS AROUND 20...EXCEPT AROUND 13 IN WIND SHELTERED AREAS. EAST WIND 10 MPH INCREASING TO 10 TO 20 MPH LATE.

TUESDAY...PARTLY CLOUDY. HIGHS 21 TO 27. NORTH WIND 5 TO 15 MPH.

Last week we received tremendous volumes of new snow on top of a fairly weak base layer. Coverage pre storm was spatially variable and we had little to no snow in some places.

The base layers showed weakness in the form of faceting.

We received about 3' of new snow last week on top of this weak base layer. This generated a great number of natural avalanches on the weak faceted layer. Some places that slid in the early part of the storm actually reloaded and slid again later in the storm. In our urban enviroment this brought slides to Snowslide Creek along Thane Road and also to the Chop Gulley Path above the Flume trail.

Many of our urban paths have still not slid. The White Path and the Berhands Path still have not seen activity. We can assume this heavy snow load is still resting atop a layer of facets in places.

After the big storm on Friday night into Saturday evening temperatures were very warm. During this warm event we received about 1.5\" of precip in the form of rain.

This affected the upper layers of the snowpack greatly but did not change the lower faceted layer much. The upper snowpack settled and bonded quite a bit since the cooling again on Saturday evening but deeper instability remains. This deeper instability appears to be MUCH less reactive than it was early in the cycle.

Now with temps below cooling this upper super saturated snow surface is starting to resolidify. It was immediately insulated with new snow Saturday evening into Sunday so it will take a little while longer to freeze completely solid. Once this occurs it should add additional stability to the upper snowpack. The tricky part is that the deeper instability remains. It will not be very reactive. It would probably take a fair amount of additional stress to trigger it, but this is a layer we will have to watch as additional load is places on the snowpack throughout the season.

As Saturdays surface layer continues to stabilize the current avalanche problem comes in the form of new snow load and wind slab. Saturday night into Sunday we had winds well into the 30+mph range out of the South to slightly SSE. Watch for increased windload on North to NNW Faces. Be aware there may be pockets of instability in these places.

It cooled slowly during this most recent snow event to current which should help with stability. This new snow came to rest on a wetted surface during an event which went from Rain to Snow. This should help with the surface bonding of the new snow.

Windload and windslabs remain the primary concern. It is difficult to say how much load it would take to make the deeper weak layer reactive once again so todays size scale is based only on the new snow and windload.

With new snow and light winds in the forecast avalanche danger will remain moderate today. Should winds or snowfall rates increase above forecasted the danger level may rise slightly.

Natural avalanches are not expected today.

Be safe out there and enjoy a beautiful day.

There is still space available for our free Avalanche Awareness Course this Saturday Dec 21st from 9-330pm at the Eaglecrest Ski Area. Companion Rescue and Stability Assessments will also be discussed.

To Sign Up Contact [email protected].

Stability Test:

Any of dozens of different tests to determine the stability of the snow.

Stability tests might include:

? Jump on test slopes (small slopes) to see how they behave
? Kick or saw off a piece of cornice and let it bounce down the slope
? Perform a slope cut
? Probe with your ski pole as you travel
? Dig down with your hand to see how well the snow is bonded to the underlying layers
? Wait for other people to jump into the slope before you
? Dig one or more snow pits in representative locations

Snowpit tests:

Most of the time we can gather enough information about the snowpack without ever taking out the dreaded shovel. But sometimes the only way to get good information about deeper weak-layers is to grease up the elbows and do some honest work for a change. I personally feel naked unless I dig at least one snowpit in a representative location to at least get the general picture of what?s going on in the snowpack.

How to dig a snowpit:

Contrary to popular belief, snowpits don?t have to take a lot of time. My philosophy is that if your feet get cold, you're doing something wrong; I almost never spend more than 10 minutes in a snowpit. Since snow can sometimes vary quite a bit from place to place, I would much rather dig several quick pits and average the results than to spend 30 minutes in one pit documenting every useless detail. We're trying to get a GENERAL, BIG PICTURE idea of what's going on here. Then move on to another location. Often I dig the hole without even taking off my skis or board, but it usually helps to at least take off the uphill ski or take one foot out of the board binding.

First, the shoveling: Get down on one knee when you shovel. Your back will thank you, and especially if you grew up Catholic, like me, it somehow feels appropriate to get on your knees when asking for answers from the unknown. Make the hole wide--about the width of a ski length. And don't dig a vertical hole, like you're going to China, shovel out the downhill side so you have room to work, which actually takes less time in the long run. Just slide the chunks of snow downhill on your shovel without lifting it. This only takes a couple minutes if you're on a steep slope (where you should be) and in soft snow (also where you should be. If not, move to a different part of the country.)

Then get your tools ready. Get out the snow saw. If you don't have one, than go buy one. You can get by without one but you will hate life and hate snowpits and you will quickly quit digging them. Not a good idea. If you're a skier, get a snow saw that fits on the end of a ski pole.

After digging the snow pit (which gives you a lot of information in itself) I like to just dive in and FEEL with my hands. Some people like to use a little whisk broom and gently brush the wall, but don't listen to them. You need to FEEL the snowpack. Run your mittens horizontally across the face of the snowpit wall and get a nice tactile feel for the different layers. Just like an eroded rock outcropping, notice how the weak layers crumble away while the strong layers remain sticking out. Then stand back and SEE the layers too. Dive in and get your hands dirty. Remember that this is not just an academic exercise. This is your life we're talking about here. Just looking and thinking don't work. Crawl around, shove your arms into the weak layers. Feel it, see it, chew on it, smell it--live it. Use as many pathways as possible--BEE the snowpack, as they say. Sometimes I wish I could shrink down to the size of a gnat and crawl around through the caverns inside the weak layer. This is how you know that you have become a complete snow nerd.

Then dust yourself off (if you're not getting snow on you, you're doing something wrong) and carefully smooth the snowpit wall in preparation for the various stress tests you will perform. Make sure it's smooth and vertical. This is very important. Remember, garbage in--garbage out. But good tests will give good answers. Whatever tests you do, they must be done exactly the same each time, so that one can compare one snowpack to another.

How deep to dig a snowpit:

Since it's difficult for humans to trigger avalanches more than about 1.5 meters (5 feet) thick, (unless they are triggered from a shallower spot) I seldom dig snowpits deeper unless I specifically know there?s a deeper weak-layer that may cause problems. If you already know that the deep layers have no worries, then just concentrate on the shallow snow. Each situation is a little different and in time you will get a feel for it. But in general, keep your snowpits less than 1.5 to 2 meters deep unless you know of a good reason to go deeper.

Where to dig a snowpit:

Where to dig a snowpit is probably more important than how to dig one. Choosing a representative location is an art, and art is difficult to describe.

Dig it on a slope most representative of the slope you are interested in but without putting yourself in danger. Often you can find a small representative test-slope--one that won't kill you if it does slide. Or, you can work your way into progressively more dangerous terrain. For instance, if a snowpit on safe terrain gives you a green light, then it gives you the confidence to dig another one on more dangerous terrain. Green light there? Then, move onto even more dangerous terrain, and so on. Never dive into the middle of a dangerous avalanche path without first gathering lots of additional data about the stability of the slope.

Don't dig it along ridgelines where the wind has affected the snow--a common mistake. Although sometimes the crown face of an avalanche may break right up to the ridge, the place where we most often trigger avalanches is 100 or more feet (30 meters) down off the ridge. Avoid thick trees because conditions are often quite different than on open slopes. Avoid compression zones and tension zones. Avoid places where people have compacted the snow.

Bottom line:
LOOK FOR NEUTRAL, OPEN AREAS AT MID SLOPE WITHOUT WIND EFFECTS.

Hot tip:

Use an avalanche probe to find a representative place with average depth. Poking around with a probe can save a lot of time digging in stupid places, like on top of a rock or tree or where a previous party had their lunch.

Many cagey avalanche professionals dig their snowpits just above a tree so they can grab it if the slope does slide. Better yet, tie a belay rope onto that tree and dig below the tree. People don?t tend to ski, snowboard or snowmobile just below trees. I almost always carry a lightweight belay rope and use it on regular basis. Most important, dig lots of snowpits in lots of different areas because the snow can vary quite a bit from place to place. Look for the pattern of instability.

Shear Quality:

What we call ?shear quality? is possibly even more important than the results of compression or Rutschblock tests. Shear quality tells you how much elastic energy is stored in the snowpack. You also hear the terms ?primed? or ?stretched rubber band? or ?sensitive? to describe the same thing that shear quality tells you. It?s difficult to describe what a high quality shear looks and feels like but you will know it when you see it. It pops out like it?s spring loaded and it does so on a clean, planar fracture. It gets your attention. Rate the shear as a quality 1, 2 or 3:

Look back tomorrow and we will discuss several simple snowpack tests you can do in your snowpits.