Soldiers, emergency workers and volunteers battled through the night to reinforce defences around Wrocław, Poland’s third biggest city, as the EU said flooding in central Europe happening simultaneously alongside wildfires in Portugal showed climate breakdown in action.

More than five times the average rainfall for the whole of September has fallen in five days on swathes of Austria, the Czech Republic, Hungary, Poland, Romania and Slovakia, triggering devastating flooding that has killed 22 people in four countries.

In Portugal, the government declared a “state of calamity” late on Tuesday night as dozens of wildfires continued to burn across northern parts of the country. The wildfires have killed at least seven people, destroyed dozens of houses and torn through tens of thousands of hectares of forest and scrubland.

Visiting Wrocław, a city of 600,000 people where the level of the Odra (Oder) River is not due to peak until Thursday, the Polish prime minister, Donald Tusk, told a crisis meeting that “a lot happened” overnight but more needed to be done.

Sandbags were passed along lines of residents and civil protection workers to fortify riverbanks and buildings, helped by some of the 14,000 soldiers sent to the worst-hit areas. Army helicopters dumped more bags to strengthen emergency dams.

Poland’s finance minister, Andrzej Domański, told the meeting 2bn złotys (£395m) had been set aside for dealing with the aftermath of the floods, which have destroyed roads and bridges, submerged whole neighbourhoods and caused billions of euros of damage.

Austria has tripled its federal disaster fund to €1bn (£840m), the chancellor, Karl Nehammer, said on Wednesday, describing the past few days as “enormously challenging” and causing “great suffering and unimaginable destruction”.

Seven people have died in Poland, seven in Romania, five in Austria and three in the Czech Republic, officials said on Wednesday, with several reported missing, as Storm Boris moved steadily westward to start threatening northern Italy.

The European Commission president, Ursula von der Leyen, would travel to Wrocław on Thursday to meet the political leaders of Poland, Austria, the Czech Republic, and Slovakia, the commission said on Wednesday.

In Hungary, authorities opened a dam in the country’s north-west to direct water from the Lajta River into an emergency reservoir to protect the town of Mosonmagyaróvár and continued to shore up flood defences in the capital, Budapest.

Authorities said the Danube River was expected to peak around or slightly above 8.5 metres, probably on Friday or Saturday. “Due to heavy rains and floods, the situation is critical all across central Europe,” the prime minister, Viktor Orbán, said. “According to the latest forecasts, the crucial time for Hungary begins on Wednesday, so flood protection is going full steam ahead.”

Elswehere, notably in the Czech Republic, waters were mostly receding, leaving an estimated €4bn of damage.

In Strasbourg, the EU’s crisis management commissioner, Janez Lenarčič, said the flooding in central Europe, combined with this week’s deadly forest fires in Portugal, were joint proof of climate breakdown.

“Make no mistake. This tragedy is not an anomaly. This is fast becoming the norm for our shared future,” Lenarčič told MEPs. “Europe is the fastest warming continent globally and is particularly vulnerable to extreme weather events.”

Beyond the human cost, member states were also struggling to cope with mounting damage repair bills and the lengthy recovery periods from disaster, he said. “The average cost of disasters in the 1980s was €8bn. More recently, in 2021 and in 2022, the damage passed €50bn per year, so the cost of inaction is far greater than the cost of action.

Brussels faces growing opposition in many member states to costly measures to combat global heating.

Critics say the bloc’s plan to become climate neutral by 2050 is unrealistic and too expensive, with populist and far right parties leading the attack. But Lenarčič said people only needed to follow the news to understand the urgency issue.

“We face a Europe that is simultaneously flooding and burning. These extreme weather events ... are now an almost annual occurrence,” he said. “The global reality of the climate breakdown has moved into the everyday lives of Europeans.”

More than 5,000 firefighters tackled more than 100 separate wildfires in Portugal on Wednesday as Spain, France and Italy each sent two waterbombing aircraft in efforts to extinguish the blazes.

“We’re in a stressful situation, at the limit of our capabilities,” the head of the Portuguese civil protection authority, Duarte Costa, told CNN Portugal, adding that the reinforcements would allow for some rotation of exhausted Portuguese firefighters and aircraft maintenance.

Portugal’s prime minister, Luís Montenegro, has paid tribute to the three firefighters who have been killed. “My deepest condolences to the families and the firefighters who died. Three heroes who gave their lives defending Portugal and the Portuguese people. The greatest tribute we can pay them is to continue fighting, as they did,” he said.

Montenegro also said the people suspected of starting some of the fires would feel the full force of the law, adding that he would “spare no effort in repressive action” when it came to such crimes.

According to data from the European Forest Fire Information Service, more than 90,000 hectares (347 sq miles) in Portugal has been burned by large-scale wildfires since Saturday, taking the total so far this year to at least 124,000 hectares. The burned area is the largest since 2017, when the country suffered two devastating wildfires that killed more than 100 people.

Italy’s national civil protection service has issued nearly 50 yellow alerts for Wednesday, warning of a risk of storms, landslides and floods in the Emilia-Romagna and Marche regions which could face two months of rainfall in the next three days.

Reuters and Associated Press contributed to this report