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How to learn from the Bostan avalanche accident, part 2:

Blog written by Arno

Last winter (on March 4th) a terrible accident happened in the backcountry of Bostan. A couple of snowshoers got caught in an avalanche a few hundred meter above the mountain hut. This morning the avalanche risk was 4 and the slope they were traversing had an angle of about 35°. Fortunately the lady could free herself. Her husband, who was ahead of her, got taken away by the slab and buried under a few metres of snow. The rescuers (and the victims wife) were not able to localise the man, because he was not wearing an avalanche tranceiver. Sadly he was only found in the spring by a walker, when the snow had melted away the metres of snow that had been covering his body during the previous months.

Read back some facts and details about the avalanche accident at Bostan
Read back eye witness Freds story about this same accident

The 1st advice, given in part 1 was:
Always bring your avalanche trinity; probe, shovel, transceiver.

avalanche trinity

Let's continue with the next pieces of advice and lessons to learn:

2: Always check the avalanche risk:

Always inform yourself about the current avalanche risk, before you undertake any off piste or backcountry activity in snowy mountains.

Avalanche flags are only visible within the skiarea and don't give comprehensive information. The daily avalanche bulletin is much more useful. So I suggest you put this Meteo France link in your Safari or favourites list, so you can always open and consult it as long you have internet connection.

Strangly only written in French, the avalanche bulletin shows your choosen area with risk factors of 1-5 indicated. In the text the current risks and dangers for the area will be further explained.

Avalanche bulletin

Avalanche risk scale:

  • Risk 5 (black flag): Stay at home if you live in a mountainous area
  • Risk 4 (black and yellow blocks): Don't go into the backcountry without professional knowlegde
  • Risk 3 (black and yellow blocks): Many slopes are suspicious and dangerous; be very sensible!
  • Risk 2 (yellow flag): There is still a risk on certain steep slopes
  • Risk 1 (yellow flag): The mountains are relatively safe, but remember that risk 0 does not exist (in winter).

Click to learn more about the avalanche scale

(Where) can I go?

I remember some people sharing their worried feelings last March, saying: “I told you that even hiking up to the Bostan hut is dangerous”.

Sorry, but I don't agree; It IS safe if you stick to the 4x4 track when you hike up to the Bostan hut. But if you leave this track and come closer to steep faces or if you climb further up after and above the hut, yes there is definately an avalanche danger and especially when there is current risk 3 or 4!

Be very careful to follow summer hiking trails in winter and following other peoples skin or snowshoe tracks in the backcountry. Don't act like a sheep; you should always ask yourself if this is todays safest option!

Skitour thumbnail

Make sure you always inform yourself about the current risk and base your decisions on it IF and where you want to go. Follow a course if you would like to learn more about interpreting the avalanche bulletin, or book a guide for your outing.

3: The 30° rule

If you stay away from 30°+ slopes you are safe(ish) from avalanche danger if the risk is between 1-3. By staying away I mean not being on, right above, under or even close to a 30°+ slope! If there is a risk 4 (or even 5) you should not be out there anyway; remember advice #2

If you want to stay away from trouble, the 30° rule is the one to remember!

This is easier when snowshoeing than when you are off piste skiing or snowboarding, but possible:


How to measure a slope angle before you go:

  • check the Geoportail website with the avalanche color markers
  • know how to measure a slope angle on an IGN map

    How to measure a slope angle when you are in the terrain:
  • different I Phone/Android apps
  • slope angle tricks with for example skipoles

If you are not able to measure or estimate slope angles, you should consider a(n avalanche) course, or again; book a guide.

4: Warning signals:

On the day of the Bostan accident these warning signals should have ring your alarm bells:

  • Signs of wind
  • Recent/current avalanche activity around you

Recent and natural avalanche activity on similar slopes might be the 'best' warning signal you could get. Noticing these kind of signs and acting upon it, is crucial and could safe your life!


There are many more warning signals to notice in the backcountry; abundant snowfall, rising temperatures, whoompf sounds, shooting cracks, etc. To recognise and interpret them well, you should follow an advanced avalanche course. Or book a guide who will notice these warning signals for you to keep you safe.


  • Always check the avalanche report before heading into the backcountry or going off-piste
  • Bring an avalanche trinity and learn how to work with it
  • Learn how to estimate, measure and interpret slope angles
  • Learn to notice and interpret warning signals

I have written down these four straight forward recommendations to learn from the Bostan tragedy. But there are many more things to learn and consider, as avalanche knowledge is very complex. I am not an avalanche expert neither, I just have interest in the subject and like to share my ipinion with you. I am pretty sure that if you learn more about these 4 pointers and start using them, you will be already MUCH SAFER out there! And that is exactly my objective with this 2 blogpost.

If you would like to learn more about the four recommendations I have given here, or just refresh your knowledge and get some practice, I am offering a pre-season safety day:

Snow-safety training day:

On Wednesday 12 December I invite you for a 1 day training that deepens your basic knowledge around snowsafety. In the afternoon you will learn how to use your avalanche trinity and we will practice a rescue operation. Price €65,-pp incl. outdoor lunch. Please send me a message if you would like to join this day or if you would like to book a private trainingday for you and your own group?


After joining this snow safety training day, you will know a little bit more about snow safety and you might:

  • Stay a way from the backcountry at all
  • Decide to take a proper avalanche course
  • Prefer to book a guide who has the knowledge about risks (but is still a human being)
  • Ignore it all and just be stupid (yes in this case we can call a warned person stupid!)

Thanks for your attention, don't hesitate leaving a comment on this post on FB and above all: STAY SAFE!

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