The Alps occupy less than 2% of Europe, yet their snow and rainfall feed the Rhine, Rhône, Po and Danube and can supply most of the water reaching some downstream regions during summer — an extraordinary amount of continental work for such a small strip of land.
Alpine runoff contributes far more to four major European river systems than the mountains’ small area suggests, especially during summer. The percentages vary sharply by basin and depend on the timing of rain, snow and melt.