Switzerland: Adverse weather forecast across much of the country through at least Dec. 13

Severe weather is forecast to occur across much of Switzerland through at least Dec. 13. Heavy rainfall is expected in alpine and western regions, with rainfall totals of around 4-7 cm (1.6-2.8 inches) expected in these regions. There is a widespread risk of flooding on the northern slopes of the Alps, around Lake Geneva, and in the Jura mountains. Landslides are possible on unstable slopes, as well as avalanches in mountainous regions due to loosened snowpack.

As of Dec. 11, MeteoSwiss has issued the following weather warnings across the country:

• Orange heavy rainfall warnings (the middle level on a three-tier scale): Across much of western and parts of central and eastern Switzerland.

• Yellow heavy rainfall warnings: Across north-central and south-central regions and parts of eastern and western Switzerland.

• Yellow flood warnings: Across much of the northern half of Switzerland.

• Yellow black ice warnings: Parts of western Grissons and northern Ticino cantons.

Red avalanche warnings have been issued across Valais Canton and into parts of central Switzerland, as well as orange and yellow avalanche warnings across most other mountainous areas. Officials could update and possibly extend the coverage of weather alerts over the coming day.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides cannot be discounted in hilly or mountainous areas, especially where the soil has become saturated by heavy rainfall. Disruptions to electricity and telecommunications services are possible where significant winds, flooding, or landslides impact utility networks.

Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger flight delays and cancellations at regional airports. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation.