Norway: Adverse weather forecast across southern regions through at least early Sept. 10

Severe weather is forecast across parts of southern Norway through at least early Sept. 10. Heavy rainfall is forecast across the region, with rainfall totals of 6-8 cm (2.4-3.1 inches) possible in the space of 24 hours and hourly rainfall rates of up to 2 cm (0.8 inches) per hour; the heavy downpours may trigger flooding and possible landslides in the affected area.

As of Sept. 9, the Norwegian Meteorological Institute has issued orange heavy rainfall warnings for parts of Eastern Norway (Ostlandet) and southern Trondelag regions, covering much of Innlandet and parts of far northern Buskerud and southern Trondelag counties. Yellow heavy rainfall warnings are in place for surrounding areas of Akershus, Buskerud, Innlandet, More og Romsdal, Trondelag, and Vestfold counties. Orange and yellow flood and landslide warnings are in place or are due to come into force in the coming hours over much of the affected area. Officials could update and possibly extend the coverage of weather alerts over the coming 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 are possible in hilly and 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 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 airports in affected regions. 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.

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.