Lisbon, Portugal
CNN
—

Large parts of Europe are being hit by deadly extreme weather conditions. In Central Europe, rivers are threatening to burst their banks due to torrential rains, and forest fires are raging in Portugal.

Seven people have died in fires in Portugal since Sunday, including three firefighters whose vehicle went up in flames on Tuesday. At least 17 people have died in what authorities have called the worst flooding in Central and Eastern Europe in decades.

The mayor of Nysa in Poland ordered the evacuation of all 44,000 residents as water levels in the city’s river rose and threatened further flooding in neighborhoods.

Grzegorz Grochowski from Nysa told how rescuers and residents brought sandbags to the riverbank. They worked through the night, into the early hours of Tuesday morning, to ensure the river did not overflow its banks.

“There was a human chain here, people passing sandbags to each other,” Grochowski told Reuters on Tuesday. “The helicopter was also carrying sand in big bags and they were dropping it to reinforce the wall all night until about 4 or 5 in the morning.”

Patients, including pregnant women, were evacuated from the town’s hospital after rising floodwaters forced it to close before all Nysa residents were told to leave. Only rescue workers and those trying to stem the river’s flow remained.

Rainfall is expected to ease through Tuesday, but authorities warn that river levels remain dangerously high and there is a risk of flooding in low-lying urban areas.

The heaviest rainfall has shifted to parts of northern and eastern Italy, where an orange rainfall warning is in effect for Tuesday.

Along Poland’s border with the Czech Republic, emergency services carried out several helicopter rescue operations in the town of Ladek Zdrój after residents became trapped in their homes.

Floodwaters have finally begun to recede after days of torrential rains wreaked havoc on rural villages. In the town of Jesenik, residents accustomed to welcoming visitors to the famous spas are instead struggling with torrents of dirty water.

Flooding has affected the width of the Czech-Polish border, extending to the city of Ostrava, where thousands of residents were left without hot water on Monday. Operators of the region’s main heating plant have ordered a complete shutdown.

Wildfires in Portugal forced authorities to close highways and roads, disrupting traffic across the country, the Interior Ministry said on Tuesday.

Fires near six highways have forced them to close, the ministry said, including the country’s main link between the capital Lisbon and the second-largest city of Porto. A total of 19 major roads have been closed due to their proximity to the flames.

More than 5,000 firefighters are battling forest fires on Tuesday as nearly two dozen large blazes rage across the country, Portugal’s Civil Protection Agency said.

Citizens have been evacuated from their homes and schools have been closed in some areas, CNN Portugal, a CNN affiliate, reported Tuesday. Much of the country remains on a yellow alert due to the risk of fires.

Huge plumes of smoke from the forest fires can be seen from space, the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) reported on Tuesday.

A spokesman for the Portuguese Civil Protection said the weather was hampering firefighting efforts as humidity remained low overnight. Firefighters normally rely on lower nighttime temperatures and higher humidity to combat the blazes, but the dry conditions had allowed the fires to spread further.

CNN Weather’s Robert Shackelford contributed to this report