A storm surge is a change in sea level from the usual predicted tidal water levels driven by weather systems.

With nearly half of the world's population living near the coast, many are at risk of the destructive impacts of storm surges.

In this video, we look in detail at what drives a storm surge and how the direction of the wind, the shape and depth of the sea floor and coastal area can affect surge formation and height.

Because this is an in-depth video, links to supporting videos that cover some of the concepts discussed will appear at appropriate times.

Written and presented by Jodie Ramsdale
Animated by Mark Machin
Sound effects: Zapsplat
Thames Barrier plaque courtesy of Steven Craven
Storm surge at Hemsby courtesy of Evelyn Simak