Car torn in half in horror crash

A man is fighting for life in hospital following a horror car crash at Windsor Gardens in Adelaide's north-east, with the impact tearing one of the vehicles involved in half.

The BMW sedan slammed into the Commodore station wagon at the intersection of Pitman Road around 2.30am.

The impact was so severe that it ripped the station wagon in half, sending parts of the car, including the engine, through the front window of a nearby electrical supply warehouse.

Its manager, Scott Southworth, told 9News he was stunned by the sheer scale of the wreckage.

"The steering wheel's ended up 100 metres down the road, we've got a battery inside our building, probably going to stop our business for a few hours (and) for this still to happen in our day and age with all the laws, rules and advertising, it's horrible," Mr Southworth said.

The driver of the BMW suffered head and internal injuries and was rushed to the Royal Adelaide in a critical condition.

Incredibly, the driver of the station wagon managed to walk away with just minor injuries. She was taken hospital in a stable condition.

A third vehicle driving nearby avoided the crash but was showered with debris.

North East Road between Sudholz Road and Fleet Avenue remained closed for most of the morning as investigators examined the scene.