Desperate families were plucked from rooftops by helicopters, cars were swept away by raging torrents and levees failed without warning Wednesday as central Europe staggered under an inland ocean of flooding.

Tens of thousands of people had to be evacuated in Germany and the Czech Republic and chemical plants along the mighty Danube and Elbe rivers were hastily shut down. City officials, federal troops and emergency workers across a vast region either raced to prepare or struggled to cope as flood crests roared downstream.

Near the southeastern German town of Deggendorf, two levees broke along the Danube and Isar rivers and their raging waters engulfed nearby houses. A southern German highway disappeared under the muddy floodwaters, cars were swept away and only the top of a few trucks peeked out above the waters.

Families scrambled to their rooftops and were airlifted to safety.

“This is an absolutely life-threatening situation,” local firefighter Alois Schraufstetter said. “Houses are covered up to 10 feet deep in water.”

Four farmers were rescued at the last minute by a helicopter airlift as floods submerged their tractor, he said. About 2,000 people were evacuated.

“We would have risked our lives had we stayed at home,” resident Hans Loefflmann said, adding that he and his wife had to leave all their valuables behind when the floods gushed into their house within minutes.

Firefighters said more than 19,000 people were evacuated from the flooding in the Czech Republic.

In the eastern German city of Halle, the downtown area flooded despite frantic efforts to protect it with sandbag barriers. Authorities urged 30,000 residents to leave their homes as the Saale river reached its highest level in 400 years.

“We fought against the water all day yesterday, and we’ve lost,” said Julia Linne, an employee at an intensive care home in Halle. “At one point we just gave up.”

In the Czech Republic, authorities said the water in the Elbe was expected to reach 36 feet early today in the country’s north, almost four times its usual height.

After inundating parts of Prague, a surge on the Elbe was now roaring north toward Germany, particularly the eastern city of Dresden, where hundreds were being evacuated.

Overall, 16 people have died since the beginning of the flooding last week: eight people in the Czech Republic, five in Germany, two in Austria and one in Slovakia. At least four other people were missing in the Czech Republic, according to the interior minister.

Hundreds of German police officers and volunteers were helping to fight the floods along with about 5,600 soldiers and 2,000 members of Germany’s national disaster team, filling sand bags, reinforcing levees and building elevated walkways to flooded homes.

“In Dresden, we have dozens of members instructing some 300 volunteers on how to build a temporary dam to hold the water back from one of the city’s main thoroughfares,” disaster team member Carolin Petschke said.

In villages around Usti nad Labem, a city of 100,000 in the northern Czech Republic, police in boats were handing out drinking water and medicine to those who had not evacuated.

Alena Lacinova despaired at how much she would have to rebuild after watching the water wash into her home. In many places, even protective barriers were unable to stop the surge.

“At the moment, we have about 8 feet of water inside. The cellar and the house are flooded,” she said, adding that she was expecting another 3 feet of water soon. “It’s a pity for all those who have the same problem and have not enough money to fix it anytime soon.”