Several people have died, two others were missing and thousands were awaiting evacuation Thursday in towns completely cut off by the worst floods in more than a century in parts of the Balkan region.
In Croatia gale-force winds uprooted trees, and record rainfall has been measured in the country's north.
In Serbia a man has died and two people were missing, while several hundred residents were evacuated as floodwaters cut off roads and flooded homes.
A state of emergency was declared in Serbia after the biggest May rainfall ever recorded caused severe flooding across the country. The measured rainfall in the capital, Belgrade, was 107.9 liters (28 gallons) per square meter (yard). The previous absolute maximum was measured in June 1994, at 94 liters per square meter.
About 100,000 homes were without power across Serbia, and 400 schools were closed. The army and all emergency services have been mobilized to help residents.
The Kolubara River has breached a dam near Obrenovac, a town of 70,000, about 19 miles southwest of Belgrade. Rescuers were rushing to evacuate nearby residents.
In western Serbia many people were forced to flee by army helicopter, taking nothing with them but the clothes they were wearing, Al Jazeera's Djordje Kostic reported from the Valjevo region.
"This is the greatest catastrophe in Serbia's living memory," said the country’s premier, Aleksandar Vucic. "Nobody can defeat water, nor fire, so saving lives is most important."
A 60-year-old man, who did not heed emergency services' warnings to evacuate from his home in Umcari near Belgrade, died in the floods.
Rescuers were searching for a firefighter who was carried by a torrent of water on the Jasenica river in Topola, central Serbia, while trying to save lives.
A state of emergency has also been declared in many parts of Bosnia and Herzegovina, where tens of thousands of homes were without power.
Maglaj, a town in the country's north, was completely under water. Defense Force helicopters were evacuating families from flooded houses, while 70 paper-factory workers await rescue inside the factory.
Many residents of Srebrenica and Bratunac, in Bosnia's east near the border with Serbia, fear they will be totally flooded if water is released from three hydroelectric power plants in Serbia, Al Jazeera's Marin Versic reported from near Bratunac. A man from the area has died from a heart attack, apparently related to the crisis.
The Sarajevo suburb of Ilidza, famous as a mineral spa from the Austro-Hungarian period, is almost completely flooded. Scores of residents have been evacuated. The Miljacka River was threatening to burst its banks and destroy bridges in several parts of Sarajevo.
Trams have been stopped in parts of the city near the riverbank.
In continental Croatia, winds of 46 mph have been recorded in the country's east and a state of emergency has been declared in the Vukovar region.
Firefighters were clearing uprooted trees and debris from the streets of Split and surrounding areas in coastal parts of the country.
State meteorologists forecast weakening rain in Serbia on Friday. Rain and showers were expected Saturday, with drier conditions forecast for the following days.
In Bosnia and Herzegovina, weakening rainfall was forecast over the next two days, and clearing by Sunday. More rain, but of a lesser capacity than this week, was expected next week.