Prague: Flood barriers and sandbags were installed and dams emptied on Thursday as central Europe got ready for what weather services predicted could be the worst floods in decades.
Forecasters in the Czech Republic and Poland said parts of their countries might record up to 400 litres of water per square metre over the next four days, while Austria and Slovakia were bracing for some 200 litres.
Cultural events scheduled for the weekend were cancelled across the four countries because of the cyclone named Boris.
Poland expected heavy rain especially in the south of the country, with cities on the Oder river including Wroclaw and Opole on high alert.
"There is a realistic risk of local inundations from Friday to Sunday," said the Polish weather service.
In Wroclaw with a population of 675,000 people, the mayor established a crisis commission as authorities emptied all retention capacities and city firefighters were ready to use high-capacity pumps.
Czech Environment Minister Petr Hladik said the situation in his country "might be similar to the one we experienced in 1997 and 2002".
The 1997 floods hit the eastern region of Moravia - where the heaviest rainfall is also expected this time - claiming 50 lives and causing damage worth billions of dollars.
In 2002, floods swept mainly the western part of the country, killing 17 people and causing damage even higher than that in 1997.
Cities in Moravia put up anti-flood barriers and prepared sandbags to battle the elements at the weekend, while local forecasters also warned against wind reaching up to 100 kilometres (60 miles) per hour.
Organisers have cancelled dozens of cultural events, including a wine festival in the southern Moravian city of Znojmo, which draws dozens of thousands of people every year.
Not far from Znojmo, the Carnuntum Roman festival in eastern Austria was cancelled as well.
"Due to the current weather situation, it is unfortunately not possible to hold the Roemerfest safely and sensibly, which is why we are cancelling the event with a heavy heart," the organisers said on its website.
Austrian TV channel ORF said the rainfall could cause the level of the Danube to rise to five-year or even ten-year-highs.
In the city of Villach in the southern Carinthia province, pedestrian walkways and cycle paths alongside the Drau river are due to be closed.
Austrian Chancellor Karl Nehammer said on Wednesday the army was ready to deploy up to 1,000 soldiers over the weekend if need be.
The Slovak army and voluntary firefighters were also on alert.
"Six- and five-kilometre-long (3.5 miles) mobile dams are on stand-by," said Slovak fire brigade chief Adrian Mifkovic.
If forecasts for Slovakia hold, the rainfall could be heavier than during the 2013 floods, which were considered a once-in-a-thousand-year event, said the imeteo.sk website.