LAKE DALLAS -- Firefighters are working to put out a five-alarm fire at a storage facility in Denton County.

The fire broke out Thursday morning in the 100 block of North Hook Street.

The facility stores boats and RVs. Some are closed, which is making it difficult for crews to fight the fire. They are having to open each unit to beat the flames.

Fire crews from Lewisville and Little Elm are at the scene. The cause of the fire is under investigation.

Check back for more on this developing story.