A 70-year-old man is in serious condition after he and his dog became trapped when a gum tree crushed his ute north-east of South Australia.

The tree fell on top of the ute as the man was driving on Warren Road in Williamstown about 11.30am today. 

Emergency responders reached the location and collaborated with civilians, using a grader and chainsaws to clear the tree.

They were able to free the man and his dog. 

The man was taken to hospital in serious condition while the dog escaped injury and is being looked after.

Emergency services then worked to clear the road as the ute was towed from the scene.

A cold front today has caused strong to damaging winds in various areas of the state, leading the Bureau of Meteorology to issue a severe weather warning.

Williamstown has felt gusts of up to 87 km/h today, with temperatures sitting around a chilly eight degrees.

Maximum wind gusts reached approximately 102 km/h at Cape Willoughby, 98 km/h at Edithburgh, 96 km/h at the Outer Harbor Tide Gauge, and 94 km/h at Minlaton Airport.