Rivers were still bursting their banks in the Czech Republic, while the River Danube was rising in Slovakia and Hungary, and parts of Austria and Romania have also been inundated by floodwaters.
The Czech-Polish border areas are among the worst-hit since the weekend, as gushing, debris-filled rivers devastated historic towns, collapsing bridges and destroying houses.
Flooding has killed seven people in Romania, where waters have receded since the weekend, four in Poland, five in Austria, and three in the Czech Republic. Tens of thousands of Czech and Polish households were still without power or fresh water.
Overnight, volunteers helped rescue workers heave sandbags to build up the broken embankment around Nysa, a city of more than 40,000 people in southwestern Poland.
National fire chief Mariusz Feltynowski said on Tuesday that the Nysa embankment was sealed, with military helicopters joining the operation to drop sandbags.
Some residents returned to check their homes were safe after evacuations on Monday, despite assurances from Prime Minister Donald Tusk that authorities would act "ruthlessly" against looters.
"(They) assured us that services would take care of our belongings and property. But we are afraid ... because we are already hearing that looters have become active," Nysa resident Sabina Jakubowska, 45, told Reuters.
Poland has declared a state of disaster in the area and set aside 1 billion zlotys ($260 million) for flood victims.
WROCLAW PREPARES
Historic Wroclaw, Poland's third city, was preparing for peaking water along the Oder river.
"We have buses provided, if there is a need for evacuation," Wroclaw Mayor Jacek Sutryk told a crisis meeting. "Today we will also be reinforcing further embankments, also in the Odra (Oder) river basin."
The city's zoo called for volunteers to help pack sandbags to protect animal enclosures and employees and volunteers began to move some of the 450,000 books from the city's main church archive to higher floors of the Archdiocesan Archives building.
Polish authorities have filled 80% of a giant reservoir near the Czech border, aimed at cutting water levels and preventing flood peaks from coinciding on the Oder and Nysa, as happened in the disastrous 1997 floods in Wroclaw.
In neighbouring Czech Republic, Governor Josef Belica said 15,000 people had been evacuated in the northeastern Moravia-Silesia region, one of two badly affected. Helicopters were delivering aid to areas cut off by floodwaters.
Credit rating agency Morningstar DBRS estimated losses from flooding across central Europe at between several hundred million euros to more than one billion euros ($1.1 billion). But Belica said the damage in his region alone would reach tens of billions of crowns (over $1 billion).
In the northeastern Czech city of Ostrava, a broken barrier on the Oder at its confluence with the Opava river caused flooding on Monday of the city's industrial area including the BorsodChem chemical plant, coking plant OKK Koksovny and others.
In Hungary, at the historic towns of Visegrad and Szentendre, north of Budapest, authorities have put mobile dams in place preparing for the Danube floods.
Budapest is preparing for waters peaking near record levels, and has closed Margaret island, a recreational area with hotels and restaurants, where people have piled up tens of thousands of sandbags to protect it.
Hungary said as many troops as necessary would be deployed to the flood-defence effort, with 1,400 already assisting on the ground.
In Slovakia, Environment Minister Tomas Taraba said the Danube had peaked at nearly 10 metres overnight and water levels would now slowly fall. He said that the damage caused by floods throughout the country was estimated at 20 million euros.
