While parched Portugal and Spain battled dozens of wildfires, emergency services elsewhere in Europe struggled to contain floods brought on by heavy rains in Austria, Bulgaria, Germany and Switzerland.
Two people were killed and two were missing after three days of torrential downpours in central and eastern Switzerland turned Alpine streams into raging torrents and triggered flooding in the country's lakes.
The latest deaths raised the total toll during the bad weather to four. Two Swiss fire fighters were killed on Sunday in a village near Lucerne after they were caught in a landslide.
Roads and railways through the Alps were cut, helicopters helped evacuate mountain homes and campsites, and schools were closed in many areas, officials said, although water levels were later reported to be stabilising.
The situation was still critical around the Swiss lakes of Thun, Brienz, Biel and Lucerne, which exceeded their alert levels.
Low-lying neighbourhoods of the capital, Bern, were partly underwater after the river Aare exceeded record levels set during floods in 1999.
About 2,500 people, including some tourists, have been granted temporary shelter in civil defence facilities or hotels in villages and towns in several areas over the past two days, reports indicated.
In Germany, flooding was worst surrounding the popular Alpine ski resort of Garmisch-Partenkirchen in Bavaria. The town, where 105 liters per cubic metre fell overnight, was almost completely cut off when the Partnach dam burst, turning the main road into a surging river and flooding hundreds of cellars.
Several rivers in Bavaria reached levels higher than those seen during the spring of 1999, when the area had its worst floods in a century.
All train traffic between Garmisch-Partenkirchen and the regional capital Munich was suspended and more than 1,000 fire-fighters, troops and police were sent to that area alone to reinforce local rescue services.
Emergency warnings were also issued in three other parts of the state.
Romania, the worst-hit country in Europe so far this summer with a death toll of 42 since June, was spared on Tuesday.
In neighbouring Bulgaria, however, the death toll from storms climbed to 26 as torrential rains flooded the north-western region of Montana.
Flood alerts were also in effect in western parts of Austria, where 450 soldiers were mobilised to help while 30 million euros (36.6 million dollars) of emergency aid was unblocked for the worst areas.
One person died in the Tyrolian region of Otztal, apparently in a landslide.
In Hungary, officials estimate flood damage at around 40 million euros.
But it was a far different story in Portugal and Spain, ravaged by wildfires and the worst drought since the mid-1940s.
Nearly 3,000 fire-fighters and soldiers battled dozens of blazes in Portugal and police found the charred body an elderly woman near her rural home.
Eleven fires raged out of control in the centre and north of the country but fire-fighters said that Coimbra, the nation's third-largest city, was no longer under threat from flames due to a change in wind direction.
The agriculture ministry said most of the country faced either a "maximum" or "very high" risk of wildfires.
Portuguese forces were backed by nine firefighting planes and helicopters rushed in from five fellow European Union nations - France, Germany, Italy, Spain and the Netherlands - after Lisbon appealed for help on Saturday.
Police said they had detained seven people, including two minors, suspected of setting fires. It raised the number of suspected arsonists detained so far this year to 105.
In the north-western Spanish province of Galicia fire-fighters battled 24 blazes, including one that has burned for three days and threatened homes near the coast west of Santiago de Compostela, local government sources said.
On Tuesday, the Spanish interior ministry said 99 people had been arrested for arson between June 1 and August 22, and that fires across the country had killed 17 people and forced the evacuation of 2,786.