The heaviest downpours here in 50 years have flooded streets and are forcing Vienna's Albertina Museum, home to landmark Impressionist works by Monet and Renoir, to move 950,000 artworks from its leaking underground depot.
The gallery, which remains open, will start moving the works on Thursday, including pieces by Flemish painter Rubens and Italian master Michelangelo.
"There has not been any damage to the works so far," gallery spokeswoman Verena Dahlitz said on Wednesday.
One of the 200-year-old gallery's most important pieces, a delicate watercolor of a hare by Albrecht Durer from 1502, has already been saved.
The collection will be moved from central Vienna to another location in Austria and the museum does not yet know how long the operation will take.
The Albertina, housed in a Neo-Classical palace which was rebuilt after World War II bomb damage, is one of Vienna's main tourist attractions, drawing a million visitors a year.
Thousands of firefighters and soldiers struggled Wednesday to contain flood waters in northern, central and eastern Austria after more than two days of heavy rain.
The situation was particularly critical in Lower Austria province where the villages of Ybbsitz and Hollenstein were temporarily not reachable by road. Water also seeped into the Medieval town of Steyr in Upper Austria province, flooding a number of buildings and streets. Towns and hamlets in the provinces of Styria and Burgenland have also been inundated.
Interior Minister Maria Fekter said the situation had improved in some — but not all — areas.
"We are constantly monitoring the situation," Fekter told reporters at a hastily called news conference, adding that 10,000 firefighters and 3,000 police officers were in action across the country.
Television images showed residents in the affected regions scrambling to secure their homes with sandbags or desperately trying to drain their basements or garages. In St. Leonhard am Forst, a village in Lower Austria, a man was photographed kayaking on a water-soaked street.
At least five rivers have overflown their banks, and a number of roads and railway lines have been closed. The Danube, the country's main waterway, was also swelling and had burst its banks in some places, including Weissenkirchen in the well-known Wachau tourist region.