Authorities in the French Alps on Friday advised climbers and hikers against taking a key access route to Mont Blanc because of a growing risk of rock-falls caused by the current heatwave.
Warning signs were put up at the Eagle's Nest viewing point near the town of Saint-Gervais after a Macedonian climber was killed Thursday on the way to a peak known as the Gouter.
"The exceptional climatic conditions have considerably increased the number of rock-falls," said Saint-Gervais mayor Jean-Marc Peillex. "We have decided to raise the alert level, but not to stop people going."
Experts in the Swiss Alps have already warned that the sun is melting ice at abnormally high altitudes, loosening the structure of the mountainside and contributing to an unusual death rate among climbers this summer.
With temperatures stuck in the upper 30s Celsius [38 celsius = 100 Farenheit] and showing no signs of falling before next week, the French were experiencing a period of summer heat unparallelled in more than 50 years.
Tourists and natives alike flocked to places that could be relied on to be cool: cinemas, museums and department stores. In Paris the underground catacombs — which have a mean temperature of 15 degrees Celsius — had to turn people away because of a quota of only 1,000 visitors a day.