Floods in Switzerland may not make the news, but if it is like Washington State and north into BC and Alaska (where there is a similar configuration of Swiss mountains) the snow melt is gradual and feeds rivers during the warmer months. When it warms too quickly or rains too hard in conjunction with the seasonal melting, then you hear about floods. This year there wasn't enough rain/snow to build up the snow pack, and the storms that hit this autumn were from offshore and causing mud slides and flooding just from the current rainfall.