Danger!!!!! What We’ve Learned About Avalanches

No, I’m not talking about the Chevrolet Avalanche, or any other SUV.  It will come as no surprise that the last time I saw one of those was before we moved to Switzerland.  This post is about snow, lots of it…tumbling down mountains.

3 = Marked Danger of Avalanches

The Alps have around 250,000 avalanches every year!  To have an avalanche, all you need is a mass of snow and a slope for it to slide down.  Specific topographic, snow and weather conditions increase the likelihood of avalanches.  They include:

  • Steep slopes of 30-45 degrees are more likely to avalanche.
  • Convex slopes are more prone than concave slopes.
  • Just looking at bowls and gullies, should alert you to their avalanche danger.  What happens when you pour water into a funnel?
  • Slopes that gather drifting snow, accumulate more of it and do it more quickly.  The snow is also looser, less compacted.  You can see how these factors all increase the likelihood of an avalanche.
  • Smooth, grassy slopes are much more dangerous because there is nothing to anchor the snow to the mountain.
  • Moist, dense precipitations are typically less dangerous than loose, dry snows.
  • Wind. It moves snow about the slopes and exerts pressure.  Need I say more.
  • Changes in temperature.  Change is destabilizing.  High and rapidly rising temperatures create wet snow prone to slides.  That’s likely what happened in the pictures below.
  • Thawing and refreezing.  When old snow melts, it becomes smooth (or icy after a rain).  It doesn’t take a genius to figure out new snow on top might slide off.
  • Similarly, loose, underlying snow is unstable.  It doesn’t take Copernicus to predict what is likely to happen.
  • A foot or more of soft, new snow is dangerous. It puts pressure on the existing snowpack.  New snow has to go somewhere, right?  Some of it might rest where it lands.  Some of it might come tumbling down.
  • Even the shape of the snow crystals can make a difference!

Avalanches can be deadly, but people buried in avalanches have a good prognosis if they are found and dug out quickly (within 15 minutes to have a reasonable chances of survival).

  • Much of North America is so large that the chances of a professional rescue team arriving in that time frame can be slim.  Nevertheless, Canada‘s average time to dig someone out is 18 minutes (with a survival rate of 46%)!  In Europe, where everything is closer, things vary by country.
  • In France, the average time to dig someone out is 45 minutes.  As a result, France’s death rate from avalanches averages 25-30 per year (60% of extracted victims die).  France (where we do most of our skiing) had more avalanche fatalities than any other country.  The winter of 2005-2006 was a difficult avalanche season and over 50 people died from avalanches in France alone.
  • Switzerland takes 35 minutes (with a survival rate of 47%).

Just last month, Prince Frisco of the Netherlands was caught in an avalanche in Austria.  He was buried under the snow for over 25 minutes and it took nearly 50 minutes to resuscitate him.  He remains in a coma and may never recover.

Avalanche deaths have been on a rise.  Equipment has improved over the past couple of decades, making “off-piste,” backcountry skiing without the benefit of marked trails composed of compacted snow, possible for many more.  It looks like tons of fun, but many are ill-prepared and not sufficiently knowledgeable.

This was taken at Les Contamines, near Mt. Blanc. If you look closely, you can see the aftermath of the avalanche.

Several technologies are essential for anyone backcountry skiing as they help improve the chance of survival.

  • Transceivers, otherwise known as avalanche beacons, send and receive radio signals, helping rescuers to quickly pinpoint the location of a buried victim.  Nevertheless, not even half of those with beacons survive.  It cannot save you if you are severely injured or buried deeply.
  • Avalanche airbags are recommended and gaining in popularity.  We have even seen them advertised at bus stops.  Worn like parachutes, the ripcord causes an airbag to inflate, encircling the head.  It  protects their head and their neck and provides floatation, decreasing the likelihood of burial.
  • Other crucial safety tools include: collapsible probes and shovels.
  • The best defense is a good offense.  It is best to avoid an avalanche altogether.

You can see where the snow slid (and might again).

Here are some YouTube links to videos of Avalanches:

During our Swiss travels in Switzerland, we have seen evidence of the Swiss infrastructure to prevent and deal with avalanches.

An avalanche shelter in Switzerland’s Lauterbrunnen Valley

Avalanche snow fences in the Jungfrau region of Switzerland

Don’t worry mom, ski resorts try to eliminate the possibility of an avalanche on the slopes by compacting the snow or using explosives.  We aren’t good enough (or brave enough) to really go off piste.

Covering to prevent snow from covering the road into the Lotschental Valley

 

5 thoughts on “Danger!!!!! What We’ve Learned About Avalanches

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