“Four people have died in Ahrweiler county, with some 50 others trapped on the roofs of their houses awaiting rescue,” Police in the western city of Koblenz said in a Twitter post.
Many of the missing people were on the roofs of six houses that were swept away by floods in the municipality of Schuld, officials said.
Search and rescue efforts were hampered by the fact that phone and internet connections were down in some parts of the county.
An emergency was declared in the region when heavy rains caused disruption in rail, road, and river transport.