Water Heater Question

While camping this weekend, I experienced something scary with my water heater. I was using electric to power my water heater. The water heater had been on the entire time, and was working perfectly. When I woke up on day three, I smelled a strange smell. I couldn't pinpoint where the smell was coming from, so I thought the smell was coming from outside. It wasn't an overpowering smell, but there was a strange smell. About 4 hours later, all of a sudden, smoke started coming out of the compartment that houses the water heater. Quickly, I turned off the water heater, and opened the compartment that houses the water heater. At this point, I could tell that the strange smell was coming from inside the compartment. I didn't see any fire, smoke, or any signs of anything burning. I opened the outside door to the water heater, and didn't see any damage either. I kept the water heater off, and only turned it on when I needed hot water. Every time that I turned it on for the remainder of my stay, I checked the water heater compartment for that strange smell; but I never smelled it again. Has anyone else experienced this before?