Homes have been evacuated across southern Germany, the Czech Republic, Austria and Switzerland as rivers reach dangerously high levels.
The Czech capital Prague is on high alert as a swell of floodwater moves in from the south.
Both Germany and Austria are deploying their armies to help emergency services.
A man was killed by a landslide near Salzburg in Austria and two people have died in the Czech Republic.
The Czech government has declared a nationwide state of emergency.