Disappointed holidaymakers are cutting short their stays in chic Alpine resorts like Zermatt and Verbier after some 80,000 tonnes of Saharan sand fell from the skies this weekend, turning Switzerland's normally pristine ski slopes a fetching shade of reddish brown.
Officials from Geneva's meteorological office said yesterday that rising water vapour sucked the sand up into huge clouds in Algeria and Morocco last Friday.
An atmospheric depression then carried the equivalent of several hundred lorry-loads of sand at around 25mph across the Mediterranean, along the eastern Spanish coast and up the Rhone Valley in France.
But when the clouds reached Lake Geneva on Sunday night, they found their path blocked by a large cold front coming from Scandinavia and turned instantly into rain, depositing their red-brown contents over a wide area and ruining the late season breaks of thousands of winter sports enthusiasts.
"We are right at the end of the season, and the slopes were already pretty far gone and icy," said a spokesman for the Verbier tourist board. "I'm afraid a light coating of airborne sand did them very little good at all."
However, the sand did wonders for the Geneva area's car washes. One main street in the city was jammed yesterday morning as queues of cars, all coated with light red dust, waited to get a wash.
Health authorities said the sand particles were too big to cause problems through inhalation, but at least one doctor in Geneva said several patients with allergies had called him in a state of panic.