A 54-year-old woman was cut out of her car and taken to hospital with serious injuries this afternoon.
Emergency services attended the collision involving the Peugeot and a van on Washington Road in Storrington at 2.50pm.
The medically trapped driver was rescued by fire crew and is suspected to have suffered a fractured pelvis.
She was taken to the Royal Sussex County Hospital in Brighton and the road was cleared by 4pm.
Motorists are being advised to take care on the roads following a Met Office weather warning for tonight (Monday) and early Tuesday morning.
Heavy rain is expected for the south-east, along with strong winds.
The public has been advised that the rainfall could cause localised flooding from rivers and surface water.
Strong gusts of wind are expected, particularly along the coast.