Whilst we often say that the Planning Phase of the Scottish Avalanche Information Service Be Avalanche Aware Process should take 75% of your time and the Journey Phase around 20% (Key Places could be 5%) it does not mean that the Journey phase is less important, in fact you could argue it is more important. So as a follow up from our earlier post about the BAA process below are some thoughts on the Journey Phase of the process.
Slope Angle - ‘If Snow is the problem then Terrain is the answer’
A saying you hear fairly often in terms of avalanche management. Whilst I think that on its own it is a little too simplistic the roots of it are correct, slope angle is one part of the process to take into account. With the majority (not all) of avalanches start (note you don’t have to trigger it to be affected, be aware of what is above you) between 30-45 degrees being able to estimate slope angle is a vital tool of any winter mountaineer as well as a Winter Mountain Leader. You will have looked at slope angle during your planning stage using maps or apps like Fat Map and then on your journey this research needs to be confirmed or proved wrong before you head onto the slope.
One way to start is to use one of a handful of tools to measure the slopes you are on (make sure they are safe before you do this). After you have measured 100’s possibly 1000’s you will become very good at estimating. However be aware that we are always prone to error so if you are ever in doubt no matter how experienced just measure it!
Map – More of a planning tool but worth mentioning here. The Harvey’s maps turn their contours grey for predominantly rock ground, however this also often equates to ground 30 degrees or more. Useful to planning but not always that accurate as they are large scale. Plenty of slides have occurred on the brown contours!
Some compasses have a built in Clinometer. Although in the photo below I have managed to get my compass dial set upside down!
Clinometer on a ski pole. Quick and effective although this PIEPS one is expensive. The Snow Angle is great and comes in various versions (some might have to be modified to be attached to a pole) https://www.slopeangel.com
App Clinometer on phone. Good and accurate but perhaps not so good for battery life of phone or worse if you drop it!
The weather: Was the forecast correct? Remember if the forecast is not what the SAIS team were given there is every chance the avalanche forecast will not be correct. Below is a great video of a key observation that can either confirm the planning info/forecast was correct or not. On this occasion if fitted with what we expected to see. So, when I see this, I am thinking is this what I expected to see? Where is the snow being deposited? Where is it coming from and what affect is it having on that area? It all goes into the thinking pot to make sure my decisions are as informed as possible.
Under foot conditions: With strong SW winds the day before we were expecting to see hard wind slab overlaying soft slab. The shooting cracks are a sure sign of a potential weakness.
This was a great example of how variable the snow conditions in Scotland can be, 10 meters SW and the slab was hard enough to take my weight, 10m NE and it was just soft slab.
Always be looking for clues and evidence on the journey to double check the planning stage.
There are plenty of other observations to be made:
Colour of the snow – Is the now grey or dirty meaning it has probably been through a melt freeze cycle and is now neve or is it bright white and so most likely fresh.
Sastrugi – a wind erosion feature that can give us some information wind direction and so areas that may have snow deposition taking place.
Rime Ice – The build up of this again can tell us about wind direction, if there has not been a thaw then the rime ice can give historical information, so you have to be careful with that!
Avalanche activity – you would think that this is one of the biggest clues, but it is often ignored. If seen do you know when it happened, is it fresh, does the weakness still exist and are you going to a similar altitude, aspect and angle?
Don’t forget the above is focusing on ‘Weather and Conditions’.
We still have to think about ‘You and Your Party’: How are you feeling, is everyone including yourself coping with the conditions, are you all communicating with each other, do you and the group have appropriate equipment for the conditions – Are any of these points affecting your decision making.
Also don’t forget ‘Mountain Landscape’ is the terrain as you expected, what is your exposure to avalanche threat (remember you don’t have to be in the trigger to be involved in an avalanche), do you have alternative plans, are you in avalanche terrain (start zone, run out zone or deposition zone).