Avalanche danger: old snow problem in Switzerland and France


By meteomorris on 18 January 2019 · 0

After an intense storm weekend the avalanche danger increased at the beginning of this week in the French northern Alps, Switzerland and Austria to HIGH to EXTREME. Since then, the snow cover has been able to set slowly and the avalanche danger has dropped significantly to CONSIDERABLE (3 on a scale of 5).

Again, don't think that it will be safer for skiers or snowboarders now. Avalanche danger CONSIDERABLE (3 on a scale of 5) is estimated by many as 'average' and gives a false sense of security. But anyone who dives deeper into the avalanche danger scale (click-click) immediately sees what it really means.

There is a significant avalanche danger when the rating is CONSIDERABLE. The snow cover is then moderately to weak on many slopes that are steeper than 30 degrees. Spontaneous avalanches of medium size are possible. The weight on the snow cover by a single skier or snowboarder may be sufficient to cause an avalanche. That sounds a lot heavier than 3 on a scale of 5, doesn't it?

TIP: check out the article 'Avalanche danger rating 3: more dangerous than you think!"

Old snow: a hidden danger

There has been no significant snow since Christmas in the northwest and west of Switzerland and the French northern Alps. It snowed again only last weekend. So that's fresh snow on an old snow layer. Those who are in the know are immediately alert. But the video below shows better what I mean.

It is a delayed recording of a snow cover test in the French Vanoise. The test took place on January 16th at an altitude of 2300 meters. Those who look closely will see the 3 conditions needed for an avalanche. A weak or slide layer, a bound layer and a slope steep enough to create an avalanche.

Such a situation occurs every winter and this results in a lot of accidents even though the danger is not visible to the naked eye. Precisely for this reason it is no bad thing to have a look at this insidious danger.

The snow of last weekend has fallen on an old and partly saccharified snow cover that is badly attached to the newly fallen snow. Although there has been a lot of snow in recent times, the new layer of snow is often too thin (especially in those places where the wind has been strong). The weight of a single skier or snowboarder can put enough pressure on the old snow layer is enough to disturb the precarious balance in the snow cover.

Defensive riding is the solution

Even for experts this danger can not be seen (it is hidden in the snow cover), so the only solution is defensive riding. Do not go too steep. This weak base layer is present almost everywhere over 2000 meters in the northwest of the Alps. It is unpredictable whether and where you are going to hit it. The use of sound decision methods is then a must.

Always check your local avalanche forecast

Always check your local avalanche forecast (here or on the destination pages on wePowder) and adapt your plans to them. Common sense and the right knowledge are the key to beautiful powder days. When you have no idea what all of the above is about, please stay on the slopes now and invest in your knowledge. Mountain Academy is the ideal start of your search for the right knowledge. You can start right away here.

Knowledge is key!


Reply

You need to be logged in to post a comment in this topic. Login or create an account.

Upgrade to wepowder Pro

  • Extended 14 day forecast
  • Slope angle and exposition terrain layers
  • Inspirational freeride routes
wePowder Pro