Eric Dane & Rebecca Gayheart -- Insane California Winds Knock Tree Down on Their House

Winds reaching nearly 100 mph are wreaking havoc on Los Angeles -- and Eric Dane and Rebecca Gayheart felt it first hand when a giant tree toppled over outside their Beverly Hills home.

Dane and Gayheart were reportedly at home at the time, but didn't get hurt. The tree -- which the LA Fire Department says was 50 feet long and weighed 800 lbs. -- also took down power lines ... so the area was sealed off.

Trees have been knocked down all over town, from Pasadena to Sunset Blvd.