Austria, Switzerland: Adverse weather forecast across both countries through at least Aug. 17

Thunderstorms are forecast across much of Austria and Switzerland through at least Aug. 17. Heavy rainfall, strong wind gusts, lightning, and possible hail may accompany storms. Heavy downpours may trigger flooding in low-lying areas and strong winds may cause property damage and power outages. As of Aug. 16, the Austrian Central Institution for Meteorology and Geodynamics (ZAMG) has issued orange thunderstorm warnings across parts of southern Lower Austria, northern Styria, and southern Upper Austria states. Yellow thunderstorm warnings are in place across most of the rest of the country, with the exception of some far northern, southern, and far western regions. MeteoSwiss has issued orange warnings for possible thunderstorms across parts of central and western Switzerland. Authorities will likely issue new alerts or update/rescind existing advisories as conditions change over the coming days.

The storms could produce rounds of heavy rainfall, strong winds, and isolated thunderstorm activity across the affected areas. 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 are possible in hilly or mountainous areas, especially where the soil has become saturated by heavy rainfall.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding, landslides, or strong winds 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. Strong winds might also pose a hazard to high-profile vehicles.

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

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.