Dynjandi (also known as Fjallfoss) is a set of waterfalls located in Westfjords (Vestfirðir), Iceland. Dynjandi is the collective name, meaning thunderous, for no less than seven waterfalls that tumble down the hillsides of Arnarfjörður.

The waterfalls have a cumulative height of 100 metres and has represented the Westfjords’ favourite frontpage model for decades. The biggest and widest part of the waterfall is the one that gets all the attention and the photos, even though there are impressive, albeit smaller, waterfalls further down the river. In fact, one is formed in such a way that the brave can walk behind it, relatively dry.