The violent storms which break upon mountain districts often cause floods of considerable magnitude, such as may be compared with the memorable bursting of the Holmfirth reservoir. Hardly a year passes without considerable damage being done: bridges are swept away; roads are buried under torrents of mud, and fields overwhelmed with débris. In August of the year 1860 a severe storm was witnessed by visitors staying at Zermatt. It began with a thunder-storm; and rain fell for about thirty-six hours, after which, as may be supposed, the torrents were swollen far beyond their usual size. Lower down in the valleys much harm was done, but there one bridge only was swept away. It was, however, an awful sight to see the Visp roaring under one of the bridges that remained, and to hear the heavy thuds of the boulders that were being hurried on and dashed against one another by the torrent. In September, 1556, the town of Locarno, in the Canton Ticino, was visited by a destructive storm and flood. The day began by several shocks of earthquake, followed, about five o'clock, by a terrific gale from the south. Part of the old castle was blown down; the doors of St. Victor's Church were burst open by a blast while the priest was at the altar; and everything within was overturned. At midday the clouds were so thick that it was almost as dark as night. A violent thunder-storm and torrents of rain followed, lasting from two to six o'clock in the evening. The rivulets all became torrents; the stream flowing through the town was so choked by uprooted trees and rocks that its water flooded the streets and almost buried them under mud and gravel. Such a sight as this gives one a powerful impression of the geological work of streams when greatly swollen; for all this débris must have been brought down from the surrounding mountains. Many lives were lost by this calamity, and a great deal of property was destroyed. Late in the year, during unsettled weather, the traveller often encounters on Alpine passes a sudden storm of snow, accompanied by violent gusts of wind, which fill the air with drifted flakes; so that becoming bewildered, he loses his way, and at last sinks down benumbed with cold and dies. Many a frequented pass in Switzerland has been the scene of death from this cause. Exhausted with fatigue, and overcome with cold, the traveller sinks down by the wayside, and the guides, after having in vain endeavoured to urge him on, are compelled, in order to save their own lives, to leave him to his fate and press forward. The name "Tourmente" is given to these storms.