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What is the point of the 1-5 Avalanche Scale?

 Poster: A snowHead
Poster: A snowHead
We all know, or we should all know, the Avalanche Scale
1 – LOW
Generally stable conditions
Triggering is generally possible only from high additional loads in isolated areas of very steep, extreme terrain. Only small and medium natural avalanches are possible.
Typical danger signs: Rarely any danger signs.
Forecast for around 20 % of the winter season.
Around 5 % of avalanche fatalities.

2 – MODERATE
Heightened avalanche conditions on specific terrain features
Triggering is possible, primarily from high additional loads, particularly on the indicated steep slopes. Very large natural avalanches are unlikely.
Typical danger signs: Often you get no danger signs, but that does not necessarily mean it is safe. Pay extra attention if Persistent weak layer is one of the avalanche problems.
Forecast for around 50 % of the winter season.
Around 30 % of avalanche fatalities.

3 – CONSIDERABLE
Dangerous avalanche conditions
Triggering is possible, even from low additional loads, particularly on the indicated steep slopes. In certain situations some large, and in isolated cases very large natural avalanches are possible.
Typical danger signs: Recent avalanche activity, cracking, “Whumpf” sounds.
Remote triggering of avalanches is typical, especially if Persistent weak layer is one of the avalanche problems.
Forecast for around 30 % of the winter season.
Around 50 % of avalanche fatalities.

4 – HIGH
Very dangerous avalanche conditions
Triggering is likely, even from low additional loads, on many steep slopes. In some cases, numerous large and often very large natural avalanches can be expected.
Typical danger signs: Widespread recent avalanche activity, cracking, “Whumpf” sounds.
Remote triggering of avalanches is typical.
Forecasted only on a few days throughout the winter.
Around 10 % of avalanche fatalities.

5 – VERY HIGH
Extraordinary avalanche conditions
Numerous very large and often extremely large natural avalanches can be expected, even in moderately steep terrain.
Very rarely forecast.


So the problem I have with this scale is that in reality % VERY HIGH is never used...so the "real" scale is 1-4, with 4 HIGH being the actual maximum indicated danger, and therefore 3 CONSIDERABLE only one step below.
However people think that 5 exists (it really does not in reality) and adjust 3 an 4 accordingly...and thus their behaviour.

I would observe that 3!=3 (I recall that those symbols mean 3 does NOT equal 3.
3 CONSIDERABLE is implemented far too early, and often hung onto for a long time, people get conditioned to it not having any avalanches for weeks and weeks and thus behave like 3 is not CONSIDERABLE.

This happened yesterday, on a 3 CONSIDERABLE day. One killed, maybe more who are suspected buried up to 5m down without transceivers, if they are there they are unfindable.


http://youtube.com/v/L9t-OAbTH6c


Firstly I think it plain wrong for it to have been downgraded from 4 HIGH to 3 CONSIDERABLE that day after heavy and prolonged snow the days before and already numerous avalanches observed and 3 dead so far in the week. Bobinch told me of having seen skiers trigger other avalanches himself yesterday, this was not an isolated avalanche.

Even so when a scale is 1-5 people just THINK that 3 is mid scale, and therefore some kind of MEDIUM risk. It is simple human nature.
Yes, I know that people should properly understand the scale....but the penalty for assuming that 3, on a 1-5 scale, is the mid point should not be risk of death!


So I ask:
What is the point of a 1-5 scale?
Abolish the never used 5 VERY HIGH, and rename the others.
Both the authorities who decide the risk warning, and then skiers who are out should get a lot more sensible about days like yesterday.
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@rungsp, we had a few days of "5" the last few winters, and it's usually in conjunction witht exhortations not to go outdoors, at all. It is really quite extreme, but not never used.

But funnily enough I was having this chat this morning. It's not a very sensible scale - I've only seen "1"s very rarely, "2"s not that often - it's mostly "3"s and "4"s.
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@under a new name, I don't think I've ever seen 1 or 5....and I am lucky to ski a lot.

So that leaves 2-4, and by far 2 and 3 are the most used....thus 3 really fails to be a warning of heightened risk.
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I discount 5 for the reason @under a new name states, the lifts are usually shut so it doesn't really count as a skiing caution level. I'd wager that 3 is the most common level, and therefore normalises it with punters who might not be completely aware of what it means and the dangers attached to it. Not sure what the solution is though. Skiing off-piste has it's inherent dangers, which is a lot of it's appeal i.e. out in the wilderness & live by your wits etc.
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I think it's pretty clear and useful. The Canadian version is similar. I did think you meant avalanche size classifications for a second there. The problem is that most of the time the risk is "considerable", and you can't sensibly chop that up because it's terrain/ location dependent, which is why the Canadian version uses the phrase "in many areas". Which area you are in matters massively.

Mostly in BC for me the snowpack is 3 or 4. So no one's going Alaskan steep... but the exposed ridges hammered by the wind are risker than deep in the trees where it's never slid.... both are covered by the same overall risk level, which is not really affected by terrain features as those depend on precisely where you are.

Quote:
I discount 5 ... the lifts are usually shut so it doesn't really count as a skiing caution level.
Yes but if you're skiing at a resort then unless you're off piste (or anywhere in North America), you can pretty much discount all of it, as someone else is looking after that for you. That's what the bombs and stuff are for. The Canadian levels are published for "Safe backcountry travel", not those hanging out on moguls at a resort.
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Plus some of the mountain users might not use lifts...
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@rungsp's frequencies of how often each level is used probably refer to the Alps as a whole. I agree that 2 and 3 are the most common.

Somewhere like Chamonix has a wetter and more changeable climate - and higher altitudes - than most of the southern Alps for example.

I think avalanche risk was 1/5 in all 9 ski areas I visited in central Italy last week. Though it was raised to 2 for my second day in Livigno, and increased to 3 the day after I flew back.

I've seen 5 several times though, including in Flaine, Espace Diamant and the Portes du Soleil. Only once (Flaine) did it result in almost all lifts being closed. Obviously it depends on the terrain.
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It's not just for skiers though. Level 5 is “danger to infrastructure”, so you probably won't be skiing that day, but the info is for the authorities to close roads, lifts etc. It's not used very often, but it is used occasionally, and needs to be there to represent that very high level when required. Ski tourers are not affected by lift closures and need to know the danger level too.

Level 1 is used regularly. Tirol has spent a week or two this season at L1, and it is currently the case in parts of Trentino (Italy) and Steiermark (Austria). L2 and 3 are probably the most used (there will be data on this, so you can look it up if interested). If you manage to time your ski trips with recent snowfall, then you will see L4 more often – I think I've only seen it for about 2 days this season.

There are nuances in the scale which are not discernible from looking at the number alone. A guide may describe conditions as a “high 3”, but you would only get this if you read the report carefully, which I know many people don't. As if often the case, the answer is education and awareness.
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@rungsp, I questioned SLF why not 4 yesterday and this was their response
big skier triggered avalanches can happen outside of danger level 4. For level 4 there normally needs to be considerable spontanuous activity, which was not the case today in Verbier. But of course with a really weak base-layer and loads of fresh snow in the past week, avalanches can get crazy big. This avalanche size was definetely really impressive and probably a size 4 (very large) avalanche. Some situations are hard to fit into the definitions of the danger levels.

The forecast said this for verbier today, which fits the situation quite well I would say:
Even single snow sport participants can release
avalanches. They can be released in the weakly
bonded old snow and reach large size. These
avalanche prone locations are to be found in particular
on steep north facing slopes and in areas where the
snow cover is rather shallow.
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phil_w wrote:
Mostly in BC for me the snowpack is 3 or 4. So no one's going Alaskan steep... but the exposed ridges hammered by the wind are risker than deep in the trees where it's never slid.... both are covered by the same overall risk level, which is not really affected by terrain features as those depend on precisely where you are.

In Austria, there are normally two levels given, with the line where it changes being roughly around the treeline (e.g. today it is L2 above 2000m, and L1 below. Sometimes it actually says “treeline”) so you can choose to stay in/near the trees for lower risk.
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I sort of agree that there is some "conditioning" to level 3. And you would not get much skiing if you never skied when it is level 3.

What is most critical is having both a more detailed understanding of the conditions on the slopes you intend to ski, and knowing how to go about making smart decisions. A simple test I employ is to ask people what the weather was a week ago for the area, if you don't know the answer I don't want to ski with you (unless with a local and trusted guide). Not in any pejorative way, it is just I only want to ski with people who prepare properly and are interested enough in their own safety to investigate properly.

Avalanche reports are publicly available and give a lot of detail. Absorbing those reports properly over a longer period is even more important than what the general risk level is on the day. Obviously being able to read the terrain and plan appropriately are also critical.

Smart decisions are much harder to make than than to say! We have all been there, with a lot of effort expended to get to an area and somehow "miss" a signal that the risk might be a bit higher than we would normally like. The best way to test this is to have a novice in the party and drill into them that their observations and questions are actually the most important. I also mentally prepare for an exit by imagining the positives in the same way as I imagine the fun/challenge of the planned descent. So when the choice comes I am hopefully more likely to see positives in either decision. But it is always hard to be sure I am really, and always, making smart decisions. Something that has to be constantly strived for.

Overall I try and see level 2 as the trigger for checking the detailed information gathering, analysis and smart decision making processes are rigorously followed. At level 4 I would only consider aspects and routes that I am absolutely sure are safe, and by that I mean no risk of being caught in a consequential slide. At level 3 I will consider the risk to be high and up the importance of striving for smart decision making.
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In resort pictograms are used to illustrate the danger: https://www.afnor.org/en/news/avalanche-risk-signage-pictograms-replace-flags/

that's relatively simple for punters to understand; basically it is 3 levels: 1 & 2; 3; 4 & 5. The difference is it is possible to mitigate the risk at level 3 by reading the bulletin and keeping off slopes mentioned as dangerous at this risk level. Level 4 is a much more generalized risk and in principal you need to keep off slopes > 30 degrees.

If you are planning on going off piste, without the help of a professional, then you really need to read and understand the avalanche bulletin and not base your decision on just the overall risk level - that figure can be used as a starting point to eliminate certain routes, not as a go!.

Going back to your example, unless you've spoken with the victims you have no idea what their motivation was for skiing the slope they were on. They may not even have looked at the bulletin or the risk level.

The avalanche risk level isn't just a finger in the air then oh heck we'll post 3 again. Risk assessment is based on well established industry practices



this is transposed by the European avalanche services into a matrix like this one



What happens is that pisteurs in ski resorts, weather observers and automatic monitoring stations feed data into the avalanche warning service. Of particular interest is information from pisteurs' observations on the ground, both during the PIDA and during the day. So today's weather, plus the forecast is used by a computer program to produce the risk matrix and the overall avalanche level: low frequency/small avalanches risk 1 to high frequency/large slides: risk 5. So if risk 3 was forecast it would have been based on observations and the weather, both over the preceeding days and forecast.

I'm not sure why years of best practise in risk assessment should be dumped. The avalanche risk scale was already reduced from 7 levels.

If you want an idea of how the danger scales up take the square of the headline risk: 1, 4, 9, 16, 25. So risk 3 is more than twice as dangerous as risk 2.

Recognizing that a lot of people ski at risk 3 the Swiss now formally divide risk 3 into upper and lower levels in their forecast - back to the 7 level scale. For example in Verbier yesterday it was risk 3+ - that should be a serious red flag to anyone.

I see risk 1 days all the time: typically in winter when there is a long period of anticyclone or in the spring, in the morning when all is refrozen and rock solid. Risk 5 is an infrastructure risk - large spontaneous powder avalanches or slides down known avalanche couloirs. It is of interest to the civil security for building evacuation or road closures - typical after big storms. Occurs once or twice in a typical winter.

Back to your question, if your off piste skiing is in high mountains in interior ranges you'll see a lot of risk 3 and 4 because those mountains have more avalanche risk. It is like saying, what is the point of a weather forecast in Serre Chevalier as they have 300 days sunshine per year. Well the forecast will tell you about the other 65 days to make sure you don't forget to pack a rain jacket, wrap up warm etc.

and given all that, the number of avalanche fatalities is very low compared to the number of people skiing off piste


Last edited by And love to help out and answer questions and of course, read each other's snow reports. on Thu 16-03-23 10:58; edited 1 time in total
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Thanks @davidof, very helpful.

Perhaps the Swiss do have 3- and 3+ but the indicators in resort (Verbier ) just have 3.
I guess we should all read the official reports every day...but I'd think not even 1% do, not an excuse but just reality.
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@rungsp, I thought the scale was universal ie not just intended for skiing. 5 is therefore a sevre warning to all people in the mountains stay indoors or evacuate the area. If you abolished 5 then how do you warn people there may be damage to property and life even for those not involved in skiing.

The problem, is not the scale but how people interpret risk, ie interpreting an ordinal as scale data. So get rid of the numbers and just use the words: perhaps:

You will be OK: only 5% of people get killed in avalanches at this level
Keep off risky terrain: only 30% of people get killed in avalanches at this level
Keep off all steep slopes 50% of people get killed in avalanches at this level, be careful
Lots of avalanches, better if you keep to the safest places: 10% of people get killed in avalanches at this level because most people are sensible and heed the advice
Very high risk of avalanches: stay indoors or leave the area: remember Galtur


Last edited by You know it makes sense. on Thu 16-03-23 11:30; edited 1 time in total
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rungsp wrote:
Thanks @davidof, very helpful.

Perhaps the Swiss do have 3- and 3+ but the indicators in resort (Verbier ) just have 3.
I guess we should all read the official reports every day...but I'd think not even 1% do, not an excuse but just reality.


The Swiss have 3-, 3= and 3+

I'm sure the bulletin is posted somewhere in resort.

What can I say? Would you go scuba diving or canyoning without checking the weather and having a full safety protocol in place?
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johnE wrote:
Very high risk of avalanches: stay indoors or leave the area: remember Kaprun


Kaprun was the funicular fire, I think that you're thinking of Galtur?
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@Kramer, You are correct. I've editted the original post
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davidof wrote:
... What can I say? Would you go scuba diving or canyoning without checking the weather and having a full safety protocol in place?
Actually I've rescued/ recovered a few people from caves now and then who've done precisely that.
Anecdotally I felt that the majority of rescues I was on were caused by that type of participant error, although google will likely show up more reliable statistics on that kind of thing.
We never got caught by the weather because if it looked like heavy rain we'd retire to the pub... not so easy for people who had booked and planned their trip months in advance.

Quote:
So get rid of the numbers and just use the words...

But you're using percentages, which we already know don't work with people like ex-PM Johnson.
The average UK person struggles with those too.
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phil_w wrote:
davidof wrote:
... What can I say? Would you go scuba diving or canyoning without checking the weather and having a full safety protocol in place?
Actually I've rescued/ recovered a few people from caves now and then who've done precisely that.
Anecdotally I felt that the majority of rescues I was on were caused by that type of participant error, although google will likely show up more reliable statistics on that kind of thing.
We never got caught by the weather because if it looked like heavy rain we'd retire to the pub... not so easy for people who had booked and planned their trip months in advance.

Quote:
So get rid of the numbers and just use the words...

But you're using percentages, which we already know don't work with people like ex-PM Johnson.
The average UK person struggles with those too.


That's the fundamental problem isn't it? For those who are bothered, they'll check anyway and the current system is adequate. For those who aren't bothered, no amount of fettling is likely to make a difference because they're not going to bother checking.
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@BobinCH and millsy have obviously turned a bit Merikin from the audio on the clip wink

Re the rest . Levels 3 and 4 are both feckin dangerous. The only difference I'd say is that under 3 your mitigation has more chance of being effective. Under 4 in reality your mitigation should be of the meadow skippy kind
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@rungsp,
Which resort(s) you talking about? I've seen all 5 levels in Tignes at various times.
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Scarlet wrote:
phil_w wrote:
Mostly in BC for me the snowpack is 3 or 4. So no one's going Alaskan steep... but the exposed ridges hammered by the wind are risker than deep in the trees where it's never slid.... both are covered by the same overall risk level, which is not really affected by terrain features as those depend on precisely where you are.

In Austria, there are normally two levels given, with the line where it changes being roughly around the treeline (e.g. today it is L2 above 2000m, and L1 below. Sometimes it actually says “treeline”) so you can choose to stay in/near the trees for lower risk.


Avalanche Canada gives 3 levels - above treeline, treeline, and below treeline. It's not unusual to have different risks at different levels.

Any scale has to cover all possibilities. But simply due to a normal distribution curve we are going to see the ones in the middle more often than the extremes at either end. So I don't think changing it is the solution, you will still have the same problems of people not understanding what they actually mean.

I'm not sure how good the euro forecasting is, but avalanche Canada do a great job. They provide a 1-5 risk score, but then a more detailed report going through each risk (i.e. windslab, pwl etc.), at what elevation zones it can be found, which direction slopes, how likely it is to avalanche, and what size avalanche it is likely to produce. If people are too lazy to spend 5mins reading the details, I have little sympathy. (Yes it's still possible to get caught out but with basic avy training, that report, and minimum common sense, you should be able to hugely minimise your risk).
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Quote:

The only difference I'd say is that under 3 your mitigation has more chance of being effective. Under 4 in reality your mitigation should be of the meadow skippy kind



Out of curiousity I attended one of the free Avalanche Academy talks in January and the presenting guide suggested that (iirc, I may be a little out) as a very broad heuristic your max slope angles should be

1 40°
2 35°
3 30°
4 25°
5 20°
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@under a new name, I think that's a little bit too conservative, but I think I know the chart you're referring to and I posted it here a few weeks ago. It has a name that I can't remember and so can't find right now Confused

[Edit] Reduction Method. Explanation here (scroll down a little for the graded chart): https://about.fatmap.com/journal-digest/how-act-in-an-avalanche-situation
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davidof - thanks really good read.

Also, and in general for what its worth, its worth remembering that if you didnt have a 5 category (and it happens occasionally and yes when it is 5 you are unlikely to want / be encouraged to leave your house!) then when its a 4 day and people are out skiing in it (e.g. yesterday) that there is nothing higher and for the majority who have never experienced a 5 day they will think 'this is as bad as it gets' and become conditioned to thinking that... but a 5 day is a whole lot 'worse' conditions wise and as happens so rarely really hammers home when its that bad that 'staying at home' is for your own good. Likewise it can stay at 2 for a long time before dropping to 1... hopefully trying to remind people that there is a danger out there or sorts! So I think a 5 scale works quite well
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davidof wrote:
rungsp wrote:
Thanks @davidof, very helpful.

Perhaps the Swiss do have 3- and 3+ but the indicators in resort (Verbier ) just have 3.
I guess we should all read the official reports every day...but I'd think not even 1% do, not an excuse but just reality.


The Swiss have 3-, 3= and 3+

I'm sure the bulletin is posted somewhere in resort.


It is available on the detailed Meteo Suisse page


There are also some very detailed profiles on the SLF site although to me they have limited value


I would agree with the comment that most people don’t look at these. They just look at the traffic light on the resort boards and then if stuff is open and tracked assume it’s ok so follow
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I recall reading about a 5 day when people were forbidden to walk down the road in Tignes - or was it Val d'Isere. And that guy had an avalanche across his bed.
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rungsp wrote:

So I ask:
What is the point of a 1-5 scale?
Abolish the never used 5 VERY HIGH, and rename the others.
Both the authorities who decide the risk warning, and then skiers who are out should get a lot more sensible about days like yesterday.


Valid question & point...

re: Cat 5.
This is basically danger to infrastructure (roads / chalets / towns).
The avalanche risk might only get to this once of twice every 5-10 years.
If it is cat 5 then the ski resort uplift will be certainly be shut and people asked to stay indoors or evacuated.
It used to by avalanche bulletin to signify risk of events like the Montroc avalanche of 1999 (where people died in their beds).
Or perhaps the Mont Blanc road tunnel being hit from above ?

Now, this raises a few problems:
Issue 1): the avalanche scale is international and standardised.
So in Scotland for example the mountains are not inhabited and a cat-5 is generally impossible
Issue 2): Although the avalanche scale is 1-5 it is actually a bell curve.
1 (basically no snow) and 5 (danger to infrastructure) are infrequently used.
So in reality the scale, for 99% of the time is 2-4.

Also : the actual avalanche danger clearly varies with aspect and altitude.
Due to, for example, wind loading or solar warming.
So even on a category 3 or 4 day there will be some slopes / aspect or times of day which are more dangerous than others.
Ultimately it is impossible to apply a single number to the avalanche risk across an entire mountain.

So in summary....
1) The devil is in the detail. Users need to look beyond the headline figure and read the bulletin itself for the real information.
2) Cat-3 is still "considerable" (rather than middle of the scale). Most educated users will know this, but wider public often ignorant.

An avalanche rose, as used by the SAIS and French, contains far more information that single number

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Now... a little though experiment about "cat-3".
If I was being cynical I would describe the avalanche scale as follows...

Cat-1: no snow
Cat-2: off piste is boiler plate / bumps
Cat-3: off piste is tracked
Cat-4: off piste is fresh
Cat-5: resort shut

However lets imagine that at cat-4 there is 10% chance if you ski random slope it will avalanche.
At cat-3 that risk might drop to <1%.
FWIW: I have made those numbers up - they depend on many real world variables, but are a reasonable guess

Clearly if you are playing the long game and ski lots then neither risk is acceptable.
I don't want to be avalanched on 1% (1/100) slopes that I ski.... Because if skiing for 30 years I will eventually be caught.

The obvious problem at cat-3 is that you can ski lots of slopes which might be "suspect" and (most of the time) nothing happens.
Because the slope didn't avalanche (even though risk was unacceptable high) the skiers think they made a "good decision".
This then reinforces the dodgy decision making process until eventually something does happen.
Hence the reason that in places like Chamonix or Verbier there are tracks everywhere on a powder day.

Ultimately humans are not very good at processing the concept of risk.

under a new name wrote:

Out of curiousity I attended one of the free Avalanche Academy talks in January and the presenting guide suggested that (iirc, I may be a little out) as a very broad heuristic your max slope angles should be
1 40°
2 35°
3 30°
4 25°
5 20°


That is the Werner Munter avalanche table. It is conservative but worth remembering if you want to reduce risk (at each level).
https://about.fatmap.com/journal-digest/how-act-in-an-avalanche-situation



Last edited by You know it makes sense. on Thu 16-03-23 16:21; edited 1 time in total
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Haggis_Trap wrote:

Now, this raises a few problems:
Issue 1): the avalanche scale is international and standardised.
So in Scotland for example the mountains are not inhabited and a cat-5 is generally impossible
Issue 2): Although the avalanche scale is 1-5 it is actually a bell curve.
1 (basically no snow) and 5 (danger to infrastructure) are infrequently used.
So in reality the scale, for 99% of the time is 2-4.


Pretty much, yes, although the level 1 is not quite so infrequent, nor only when there's no snow. It was L1 for pretty much the last month across the PdS until last week's snow came, No new snow, sure, but it's a perfectly valid and meaningful measure, not that uncommon, and particularly relevant for ski touring off the beaten track.

L5, yes, you're pretty much never going to encounter this on any day that you could conceivably want to ski, and anything bar low flat bunny slopes are very unlikely to be open. I don't think I've ever seen it in am open ski resort.

The chart showing levels of steepness fails to take into account steeper slopes. Above 50degrees or so the relative risk actually drops, because it's very unusual for snow to stick around long enough. ISTR a figure of 53 degrees being used in some of the avalanche courses I've done over the years. But there can be slope steeper than that which accumulate snow due to unusual geography - there's one particular gully near the top of the Laub in Engelberg which I've personally measured at 60 degrees; wind whipping around compacts the snow and it holds very well indeed. That gradient continues for around 10-15 turns, then you stop, look up at the underside of your mate's skis or board and hear them whooping their way down, only then realising that you're _still_ on a 45+ degree gradient. Glorious.

Personally I think the scale is pretty useful and meaningful as it is and can't see any reason to change it. It's not entirely done for the benefit of recreational skiers, after all.


Last edited by Otherwise you'll just go on seeing the one name: on Thu 16-03-23 16:20; edited 1 time in total
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Shush, your not allowed to say there was no snow - people get quite upset wink

The level is pretty much 1 over most of Iceland most of the time, because most of it's flat and all that.
But even the bits which aren't can be very safe in the right conditions.

So I think we've decided collectively that the scale is actually quite good for what it does.
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There is massive variation in level 3. When there’s fresh snow it always goes up to level 3. If there’s a lot of snow and it’s accompanied by high winds it goes up to 4 (quite rare) and usually only stays at that level for a day.

Most of the time I see little avalanche activity after fresh snow - level 3. If it snows without wind you can get 1m and nothing moves. It would still be risk 3. Yesterday there was avi debris everywhere and several big slab slides catching people at level 3.

Neither the avi level, nor report sufficiently reflect the huge variations seen on the ground IMO.

I still think yesterday should have been avi 4 base on the amount of snow, wind and visible avi activity?

But that would have kept the high lifts shut and penalized all those people just using the pistes.

Not an easy one…
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BobinCH wrote:
There is massive variation in level 3


^ Very fair point... Cat-3 can cover a very wide range of conditions. Within that there will be variations with aspect and altitude. A 3+ days feels very different to a 3- where risk night be localised and manageable.

Annecdotally my experience is the SLF seem reluctant to use cat-4 (unlike french where it is much more common). Watching your video it looks like a cat-4 day to my eyes... Large spontaneous avalanche? Though forecast is technically the risk of avalanche (rather than subsequent size).


Last edited by Well, the person's real but it's just a made up name, see? on Thu 16-03-23 16:51; edited 1 time in total
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Quote:

the level 1 is not quite so infrequent, nor only when there's no snow


Agree, certainly in Canada plenty of days most winters where below treeline and treeline are level 1.

Quote:

Cat-2: off piste is boiler plate / bumps
Cat-3: off piste is tracked
Cat-4: off piste is fresh


Following storm in Canada:
Day 1 - No real need to go out of bounds as better to just enjoy the in bounds avy controlled terrain. Usually they don't get everything open.
Day 2 - No real need to go out of bounds as lots of fresh tracks to be had on the stuff that wasn't open yesterday but now is.
Day 3 - Consider out of bounds if avy risk has lowered a bit.

I guess there's not the luxury of lots of in bounds avy controlled off piste in Europe, which makes for more competition and dangerous decision making.
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Anyway, snowHeads is much more fun if you do.
boarder2020 wrote:


I guess there's not the luxury of lots of in bounds avy controlled off piste in Europe, which makes for more competition and dangerous decision making.


This is a myth IMO. There’s tons of safe controlled terrain on sides of piste and itineraries and everything under 30%.

But there are also (relatively) easily accessible areas that are not controlled. And a few unlucky people get caught each year. But however stupid you are you still need to be extremely determined and unlucky to die as the relatively tiny number of fatalities vs the huge number of skiers in the off piste shows.
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As a complete novice in this subject - you all know much more than me and this thread is brilliant - I think the current 1-5 scale is very good when used with the avalanche rose.
I have seen all levels in resort over the years.
The problem is most holiday skiers don't think past it's a holiday therefore it must be safe.
I am probably in a minority, I was given a book by a guy called Bruce Tremper which basically said there is no such thing as a safe day in the mountains. You will get slides even on a level 1 day.

I am on a Crystal package now and I get morning bulletins from them about the Avi risk. Very simple ones it's true but even so I think this is a step in the right direction.

Just thought you'd like a novices input! Very Happy
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BobinCH wrote:
boarder2020 wrote:


I guess there's not the luxury of lots of in bounds avy controlled off piste in Europe, which makes for more competition and dangerous decision making.


This is a myth IMO. There’s tons of safe controlled terrain on sides of piste and itineraries and everything under 30%.

But there are also (relatively) easily accessible areas that are not controlled. And a few unlucky people get caught each year. But however stupid you are you still need to be extremely determined and unlucky to die as the relatively tiny number of fatalities vs the huge number of skiers in the off piste shows.


Are side of pistes and itineraries always avy controlled? Where does side of piste become off-piste? How many of us can accurately judge slope angle, which is often not particularly uniform.

I like the very black and white set up of n American resorts. I also don't think the vast majority of euro itineraries and controlled Freeride areas come close the kinds of accessible in bounds stuff in n America.
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@BobinCH,

I know what you mean, but tell that to the insurance company if someone injured themselves off-piste without the requisite cover.

@boarder2020,

It’s black and white in Europe as well. Marked pistes are controlled, nothing else is.
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BobinCH wrote:

I still think yesterday should have been avi 4 base on the amount of snow, wind and visible avi activity?


Pretty sure I got a L4 warning from the Swiss Emergency Alert app yesterday. Didn't check the local one, as I wasn't skiing, but it does perhaps go to show that the national/regional assessments may sometimes be different from those posted by resorts, on the basis, I assume, that a resort one is also taking into account actual conditions and geography of the resort rather than the more general area risk.
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Interesting discussion and information.

I ski off-piste but it’s more side piste and/or areas I know (Siviez fields or the itineraries). I’ve been skiing mainly the 4 vallees for about 15 years and I’ve seen where it does and doesn’t avalanche. For example it can sometimes avalanche onto Chassoure and it avalanches a lot if you go round the corner. I don’t.

I remember a statement in a video that approximately 90% of fatal avalanches occur within 24 hours of the snow falling and the majority of those are skier/boarder triggered.

It does seem a bit of a numbers game. If you ski that type of stuff often enough.

I did hear there was a fatal avalanche at Stairway to Heaven but don’t know if it was the climb in or on the down side. Bob ?
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