Switzerland: Adverse weather forecast across central, eastern, and southern regions June 21

Severe weather is forecast across parts of central, eastern, and southern Switzerland June 21. Heavy showers and thunderstorms are forecast across the affected area; strong wind gusts, lightning, and possible hail may accompany storms. MeteoSwiss has issued orange thunderstorm warnings (the middle level on a three-tier scale) with a high chance of occurrence across parts of central and northern Ticino and far southwestern Grissons cantons. Orange thunderstorm warnings with a low chance of occurrence have been issued across the rest of southeastern and east-central Switzerland. Yellow heavy rainfall warnings have been issued across much of the rest of central, eastern, and southern Switzerland. 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.