Snowploughs were needed to clear hail in Munich and a Berlin museum was flooded when lightning and torrential rain lashed Germany during the night, emergency officials said Saturday morning.

At the Allied Museum in Zehlendorf, Berlin, dedicated to the US, British and French occupation of Berlin from 1945 to 1994, local floodwater entered the building's lowest level but did not damage any exhibits.

Elsewhere in the capital, main roads were swamped when drains choked.

In Bavaria state, high winds ripped roofs off 10 houses and toppled trees, while the hail was so heavy that Autobahn 8, one of the main freeways near Munich, was closed because it was too slippery.

Emergency services called out ploughs that are on stand-by in winter-time to clear snow.

A tornado hit the northern state of Lower Saxony, damaging tiled roofs and ripping up trees.