GRESHAM, Ore. – A jet-ski exploded in the driveway of a Gresham house on Sunday evening, badly burning both the man who was working on it and the outside of his home.Fire investigators are still piecing together what happened, but it appeared the jet-ski exploded in the driveway of a house in the 600 block of SW Mawrcrest Drive and the fire spread to a car parked nearby and to the garage.Neighbor Cayla Perez said she was at a park behind her house when she heard the explosion.“We just heard a big boom and saw smoke pouring out and we thought it was our house, so we ran here really quick,” she said. “It was pretty dramatic. It was just a big boom. I thought a car crashed into a pole, or gunshots – it was really loud.”The man was taken to the Legacy Emanuel with severe burns, but was expected to survive.The fire didn’t spread to the inside of the house.By KATU.com Staff [fblike]