Denmark: Adverse weather forecast across most of the country through at least Jan. 4

Severe weather is forecast across most of Denmark through at least Jan. 4. A storm system is forecast to bring a mix of heavy snowfall and rainfall as well as strong winds across many parts of the country. Rainfall totals of 3-8 cm (1.2-3.1 inches) are expected across southern and eastern regions. Snowfall accumulations of up to 30 cm (12 inches) with localized higher amounts are expected in northern parts of Jutland. The combination of heavy snowfall and strong winds may lead to blizzard conditions in places and hazardous travel conditions are likely in affected areas. Disruptions to both road and rail transport networks are being reported in Aarhus and surrounding areas of Jutland as of early Jan. 3. Sustained heavy downpours may trigger flooding in low-lying areas and strong winds may cause property damage and power outages.

As of Jan. 3, the Danish Meteorological Institute has issued orange blizzard warnings (the middle level on a three-tier scale) across the northern half of Jutland and surrounding islands. Orange heavy rainfall warnings have been issued for Zealand and other eastern islands and yellow heavy rainfall warnings for the southern half of Jutland, Funen, and surrounding islands. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change 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 or a lack of stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall.

Precipitation will likely fall as snow in parts of Denmark over the coming days. Wind gusts could cause blowing and drifting snow; decreased visibility is likely in mountainous areas. Rain-induced landslides cannot be discounted in areas of elevated terrain; there is also the possibility of avalanches in mountainous areas where the snowpack has become unstable due to heavy snowfall. 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. Heavy snow will likely make driving hazardous in some areas; authorities could implement temporary road closures or detours in such locations. Mountain passes and tunnels could be closed as a precautionary measure during periods of intense snowfall.

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.