The Diavolezza glacier, and the long 1,000 vertical metres descent from the top of it, remains open in the Engadin, close to St Moritz, in Switzerland. Only one run is open, and snow depth is down to 20cm (eight inches) at the 2,000m base of it (60cm/two feet at the 3,000mm top) but it's one long run to be skiing in late May! The other choice is year-round ski destination Zermatt, which continues to operate its ski lifts on the continent's highest runs, touching 3,900m.