A tourist visiting Yellowstone National Park said she and her family emerged from a restroom break at a welcome center to find a large snake emerging from the engine of their vehicle.

Alisha Archuleta Peterson of Utah said she and her family were on the final day of their six-day vacation when they stopped at a Yellowstone welcome center to use the restroom.

They came back outside to find a crowd of onlookers watching the large snake slithering out from the engine compartment of their SUV.

"I was not getting in the car until he came out," Peterson wrote in a Facebook post.

Peterson said her husband and her father attempted to get the snake out of the SUV, but they were unsuccessful. A nearby snake enthusiast offered to help, and he was soon joined by two park rangers.

The snake was finally removed after more than an hour of attempts, she said.

Peterson said an onlooker told her the serpent was a non-venomous bull snake.