The worst of the European heat wave may have ended, but for Alpine climbers the disastrous summer continues. In July, the Matterhorn was briefly closed to climbers and more than 70 were evacuated by helicopter after huge rockfalls swept the east and north faces. Now, for the first time in history, guides in Chamonix have stopped leading climbers up 15,771-foot Mont Blanc, as the exceptional heat has exposed unstable ice walls and rubble fields. According to newspaper reports, the summit of 14,121-foot Dôme du Goûter, midway along a popular route to Mont Blanc, is bare of snow for the first time in memory. A key section of the Walker Spur on the Grandes Jorasses reportedly has fallen off, and rockfall is making other routes throughout the range completely impassable. Officials fear that ski lifts, cable cars and mountain huts whose foundations are anchored in permafrost may be permanently damaged by melting ice.