Europe: Adverse weather forecast across much of southeastern Europe through at least April 5

Event

A combination of heavy snowfall, rainfall, thudnerstorms, and strong winds are forecast across much of southeastern Europe through at least April 5. The affected area includes parts of Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Greece, Kosovo, Montenegro, North Macedonia, Romania, Serbia, and Slovenia. Heavy downpours could trigger flooding in low-lying areas and strong winds may cause property damage and power outages. Thunderstorms may be accompanied by lightning and hail.

As of April 3, the various meteorological institutions of the respective countries have issued the following weather warnings:

• Red (the highest level on a three-tier scale) strong wind warnings: Rijeka Region and most coastal waters of Croatia; and across south-central and southern Montenegro
• Orange heavy rainfall warnings: Across much of Greece with the exception of Attica and southern island regions; across Kosovo; across North Macedonia with the exception of eastern and northeastern regions, and eastern and southeastern regions of Serbia
• Orange snow warnings: Across Kosovo; parts of northwestern North Macedonia; parts of the eastern and southern Carpathian mountains in central Romania, and southeastern and southwestern regions of Serbia
• Orange thunderstorm warnings: Across much of Greece with the exception of Attica and southern island regions
• Orange strong wind warnings: Parts of southern Bosnia and Herzegovina; Dubrovnik, Gospic, Knin, Split, and Zagreb regions as well as northwestern coastal waters of Croatia; across northern and north-central Montenegro, and northeastern, southeastern, and southwestern regions of Slovenia
• Yellow heavy rainfall warnings: Across western and west-central Bulgaria; Attica, Crete, and the Cyclades Islands in Greece; eastern and northeastern regions of North Macedonia; much of central, eastern, northeastern, southern, and western Romania, and southwestern Serbia
• Yellow snowfall warnings: Parts of central, eastern, and southeastern Bosnia and Herzegovina; across northern and north-central Montenegro; parts of western North Macedonia; much of central, eastern, northeastern, southern, and western Romania, and western Serbia.
• Yellow thunderstorms warnings: Attica, Crete, and the Cyclades Islands in Greece
• Yellow strong wind warnings: Across parts of northern, southern, and western Bosnia and Herzegovina; across most island regions and parts of northern Greece; parts of central and southern North Macedonia; much of central, eastern, northeastern, southern, and western Romania; parts of northern Serbia, and central and northwestern regions of Slovenia
• Yellow cold temperature warnings: Parts of central, northwestern, and western Bosnia and Herzegovina, and much of central, eastern, northeastern, southern, and western Romania
• Yellow rough sea warnings: Southern coastal areas of Montenegro

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days. 

Hazardous Conditions
The storms could produce rounds of heavy precipitation (including rain and snow), strong winds, and isolated thunderstorm activity. Where precipitation falls as rain, flash and areal flooding may occur. Such flooding is possible in low-lying communities near watercourses and other large bodies of water and in urban areas with easily overwhelmed stormwater drainage systems. Sites downstream of large reservoirs may be subject to flash flooding after relatively short periods of intense rainfall.

Precipitation could fall as snow at higher elevations 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. Power outages could occur throughout the affected area.

Transport
Floodwaters and related debris may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around the affected area. Flooding in urban areas could also result in significant traffic congestion. Heavy snow could 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.

The disruptive weather may cause some delays and cancellations at airports in the region. Authorities may temporarily suspend port operations in coastal areas if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas that see heavy rainfall and potential track blockages.

Disruptions triggered by inclement weather and resultant hazards, such as flooding or avalanches, could persist well after conditions have improved - it could take days before any floodwaters recede and/or officials clear debris. If there is severe damage to infrastructure, repair or reconstruction efforts may result in residual disruptions.

Advice

Monitor local media for weather-related updates and advisories. Confirm all transport reservations and business arrangements before traveling in the affected area. Seek updated information on road conditions before driving or routing shipments through areas where severe weather is forecast; plan for possible supply chain disruptions throughout the affected areas. Stay away from elevated streams, creeks, and other watercourses that are prone to flash flooding. Do not attempt to navigate flooded roadways. Exercise caution in elevated terrain due to the threat of landslides, as well as mountainous regions where avalanches pose a threat. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

Meteo Alarm
Bosnia and Herzegovina Federal Hydrometeorological Institute 
Bulgaria National Institute of Meteorology and Hydrology (NIMH)
Croatia Meteorological and Hydrological Service (DHMZ)
North Macedonia Hydrometeorological Service
Romania National Administration of Meteorology
Republic Hydrometeorological Service of Serbia
Slovenia National Meteorological Service