Breaking: Four seriously injured after car hits caravan in WA

A child is among several people critically injured in a serious road crash in WA's Gascoyne region.Emergency services were called to the scene of a two-vehicle collision south of the Overlander Roadhouse near Shark Bay at around 11:30am.St John WA paramedics treated four people at the scene and conveyed them to Shark Bay Airport, a remote runway 830 kilometres north of Perth.They were met by the Royal Flying Doctor Service's emergency jet at 3.15pm, which plans to transport a child with life-threatening injuries to Perth Children's Hospital for further treatment. The North West Coastal Highway has been closed between Overlander Roadhouse and Billabong Roadhouse. (Supplied: Rhys Chivers)The other three are being triaged on the runway. An RFDS spokesperson said it is uncertain whether they too will be evacuated. The North West Coastal Highway has been closed by WA Police and motorists are being asked to avoid the area.Dozens of vehicles have stopped at the nearby roadhouse during what is the peak tourist period for the region.