Deadly Swiss Avalanches, in Maps

In my previous post, I explored a dataset on fatal avalanches in Switzerland from the Swiss Institute for Snow and Avalanche Research (SLF). The dataset also contains the location of each avalanche, and here I’ll explore a few ways to show the data geographically.

In the map above, the location and date of each avalanche is used to make a time lapse with CartoDB’s Torque function. Each flashing white marker is one fatal avalanche. Besides the general location of avalanche risk in Switzerland and the seasonal pulsation of events, this map does not convey all that much information. However, I think it is worthwhile because it drives home the sheer number of deadly avalanches – 361 – during this period. We have to keep in mind that each of these flashing markers is a separate tragedy that together represent the loss of  465 lives.

This map shows the geographical distribution of fatal avalanches by the activity or location involved in the accident. As I discussed in the last post, the great majority occurred in open country during recreational activities like backcountry touring or off-piste skiing. The map illustrates that backcountry touring accidents are distributed fairly evening across the high Alps, while off-piste skiing and snowboarding accidents tend to be clustered. Closer inspection reveals that these clusters occur around high mountain lifts, like this, the largest cluster, one on the north slope of Mt. Gele and Mt. Fort near the resort of Verbier:

Screen Shot 2016-04-01 at 9.43.47 PM

This map also lends itself well to exploration. The Open Street Map base has great detail upon zooming, and you can click on each point to get more information about each avalanche, such as elevation, aspect, date, and number of fatalities.

Finally, here’s a heatmap showing the density of fatal avalanches, with red areas having the highest densities. The cantons of Valais (in the southwest) and Grisons (in the east) have the highest concentrations of deadly avalanche accidents. I used a Landsat mosaic as a base map, which allows for comparison of the relationship between terrain and avalanche density.

All avalanche data from WSL Institute for Snow and Avalanche Research SLF, 25 March 2016. Data and code available here. Maps generated using CartoDB.

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