On Saturday April 28th 2012 most of Chamonix Mont Blanc was without power for 14 hours through until late Sunday morning. A very strong foehn wind storm attacked Chamonix, causing extensive damage to the town where hundreds, if not thousands of trees came down. People who have lived here all their lives say it was the strongest wind episode to hit the valley since 1967.
Measurements of the gusts were initially 150km/hr from the downtown Chamonix weather stations, and then upgraded to 180km/hr. Normally winds this strong stay up in the high mountain and the valley is protected. But in this case the gusts were racing down from the Mont Blanc side of the valley down to the valley floor, and up the Aiguilles Rouges side. The gusts caused a wave-like action bouncing off the valley sides – this caused the tree branches to spin around violently and is what pulled many trees down. Others came down because trees above them fell into them – in some sections of the woods above Les Bossons on the south side, I saw sections of 20 trees all felled by one or two originally tumbling. On the other side of the valley, the Blaitiere section must have had a wind blast that was incredibly strong – a huge swathe of trees had been snapped literally in half by a blast which then raced down into the Montenvers car park, smashing in the windows of many vans and cars parked there.
Some roofs were ripped off of chalets and refuges, giant healthy old trees were uprooted if they would not break or were snapped in half like twigs; garden furniture and anything not nailed down was blowing around dangerously all night long. The Aiguille du Midi lift station lost power for most of the night, the Montenvers tourist train was out of commission for a week after the storm while crews cleared hundreds of trees from the tracks and replaced some of the electric towers. Argentiere was less affected but trees came down onto at least one home along the roadside, and the roof of the Refuge du Lognan was ripped completely off. In the moraine area near the Cremerie du Glacier restaurant in Argentiere many trees came down – most of those had shallow root systems.
I took a few photos of some damage in my neighbourhood which are posted on Flickr (click the image above to reach the site for more images). The photos are not particularly spectacular in an artistic way, but they do illustrate just how strong a force the wind can be. Trees we never would have expected to come down due to their size and seemingly good root systems did come down.
What was amazing was that no one was seriously hurt or killed in this storm despite the extensive damage. Clean up is proceeding – the repair crews did a great job of getting all the critical roads open very quickly and now the trail teams are working their way from the valley floor up in altitude clearing the trails for hikers this summer.
On the positive side, sales of chainsaws and auto glass repairs are up – good for those businesses ! And many people will not need to purchase firewood for next winter. Weekends since then have been set to a sound track of many chainsaws whining in all directions surrounding us. I imagine the insurance claims departments are somewhat overloaded.