OAKLAND  (AP) — San Francisco Bay authorities searched Sunday for a person who may have jumped into the cold waters adjacent to Oakland Airport after ramming a pickup through a perimeter gate while fleeing a sheriff’s deputy.

Several hours of searching were unsuccessful, raising the possibility the person succumbed to hypothermia, Alameda County sheriff’s Sgt. Ray Kelly told The Associated Press.

Kelly said flights were shifted to the airport’s north side runways but there were otherwise no disruptions to airport operations.

The pursuit began around noon when a deputy tried to pull over the vehicle for running a stop sign, Kelly said.

The pickup went down a service road, blew through the gate at 50 mph (80 kph), sped over dirt trails along the perimeter and at one point got onto a taxiway, Kelly said.

The person was last seen on foot running toward the bay, which runs along the airport’s south runways. A dog also trailed a scent to the water.

“You get in that water and you’re looking at a rapid hypothermic onset,” he said, adding that the search could turn into a recovery operation.

Investigators were trying to determine the person’s identity.

Kelly said at first look there appeared to be a stash of weapons in the truck but they turned out to be so-called airsoft guns that shoot plastic pellets and are typically used in competitions simulating military tactical situations.