Massive windstorms on Arrakis caused by the interaction of the planet's rapid rotation with its extreme temperature differentials between day and night sides. These storms could reach wind speeds of several hundred kilometres per hour, carrying enough sand to strip flesh from bone. Coriolis storms were one of the greatest dangers of desert travel, and the Fremen developed sophisticated methods of weather prediction and shelter construction to survive them. The storms also played a role in spice production by exposing pre-spice masses to the surface.