Switzerland: Adverse weather forecast across southern regions through at least May 16

Severe weather is forecast across parts of southern Switzerland through at least May 16. A low-pressure system is expected to bring heavy rainfall to the south side of the Alps, with rainfall totals of 10-15 cm (4-6 inches) possible in central and southern parts of Ticino Canton and totals of 8-10 cm (3-4 inches) possible in parts of northern Ticino and southern and southwestern Grsisons cantons. MeteoSwiss has warned of possible flooding in the region due to continuous heavy rainfall.

As of May 15, MeteoSwiss has issued the following weather warnings across the affected area:

• Orange heavy rainfall warnings (the middle level on a three-tier scale): Across southern and south-central parts of Ticino Canton.

• Yellow heavy rainfall warnings: Across the rest of the affected area

Officials could update and possibly extend the coverage of weather alerts over the coming hours and days.

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.