A man described as an "experienced skydiver from Toronto" is lucky to be alive after experiencing problems with both of his parachutes after jumping from a plane 600 metres above the Hamilton airport on Thursday.

Police say the 44-year-old man was skydiving above John C. Munro International Airport to mark the 75th anniversary of D-Day.

Moments after jumping from the plane, his primary parachute became tangled.

He deployed a second parachute that also didn't open properly but managed to slow his fall with just 30 metres before he hit the ground, police said.

"It was terrifying, to say the least. Poor guy," said Marianne Hobson, who saw the man fall.

Hobson said she was at the airport to take photos of the jump when she noticed, through her zoom lens, that one of the parachutes didn't open. She said his second parachute opened with just enough time to slow his fall but he "crashed off the course into some trees."

Hobson said a medic in the Air Force Reserves rushed, along with others, to help. She said she was told that the man was "talking and aware."

"Somebody was looking out for him that day, for sure," Hobson said.

Police say the man was taken to hospital after suffering non-life-threatening injuries. Transport Canada has been notified.