The spell is negated inside a 5 foot radius around your person when cast. Everywhere else in a 30 foot radius around you becomes rough terrain cause by gale-force winds 

When a creature enters or begins their turn within the radius they must make a Dexterity Saving Throw. On a failed save they take 2d8 force damage and are knocked prone. On a successful save they take half damage and are not prone. Add an extra d8 to damage for every level over 5.