Maps Lie

You see the box to the right of this report that says the Swiss border is 2,000 kilometers?

That might be literally close to accurate, but it’s a lie in terms of telling a true story. The linear distance is as nothing compared to the reality of tracing those kilometers up and down hills, traversing fields of loose rocks, or, like parts of today, weaving through mazes of crevasses. A crevasse maze might require three or so times the walking as a map would imply; more if the maze lead to a dead end and you have to retrace your steps. But they are also really fun, an intellectual challenge that unfolds as you go. And there’s a bit of spice whenever you walk across an ice bridge and peer dozens of meters into the abyss on both sides, hoping that you’re right that an extra 70 kilos won’t make it break.

We spent nearly the whole day on ice, but the mazes just occupied a few entertaining hours. Most of the time the crevasses were small enough to hop over, and the ice was generally fast to cruise across, just as good as a trail.

Another way the map lies is simply by being out of date. Our map was supposed to be accurate as of 2003, but this is 2011 and where the map says there’s a glacier maybe there is, or maybe it’s gone. We crossed talus fields where the map said would be ice.

Though we haven’t seen any, a big problem in some places with retreating glaciers are the lakes that form behind soft moraines as the glaciers receed. Sometimes the dams holding back these lakes break, resulting in what’s known as a glacial lake outburst flood, or GLOF. These can cause flash floods to sweep down the valley, wiping out villages below. It’s generally a problem of receeding glaciers in warming times like our own, but the valley just below the Chandrion Hut where I am now experienced a similar problem way back in 1818, when the glaciers were still advancing.

An older mountaineer at the hut this afternoon told me that he had recently read that the Gietro Glacier, just a few kilometers north of here, surged until pieces broke off and filled the canyon below, blocking the Mauvoisin river and causing a lake to build up. Townspeople grew seriously concerned about more ice falling into the new lake and sending waves of water surging downstream. So they sent up engineers and laborers and carved various tunnels that were supposed to drain the overflow if it were to rise higher. They did masterful work that should have solved the problem except that they overlooked one thing. When the next piece of glacier dropped into the lake the ice split into pieces that clogged all the tunnels, rendering them useless. Water washed over and flooded the valley, killing 34 people in Martigny down in the Rhone Valley. At least that’s the story as I heard it, one of so many that I look forward to exploring in more depth.