ROQUE BLUFFS, Maine — A pregnant Maine woman and her friend visiting from Pennsylvania got lost hiking and were rescued but died later that evening, authorities said, when they accidentally drove their car into the ocean in the nighttime fog.

Amy Stiner, 37, of Machias, and Melissa Moyer, 38, of Sunbury, Pa., presumably drowned when Stiner drove her minivan down a boat ramp at the end of a dead-end road at about 9 p.m. Tuesday in this town of 300 people in eastern Maine, said Washington County Sheriff Donnie Smith. He called the deaths a tragic accident made worse because Stiner was five months pregnant.

"They called on the phone that they were in the water and the car was filling up. Then the phone went dead," Smith said. "An hour later, the deputies found the car."

Earlier in the evening, the women hiked in Roque Bluffs State Park but got lost and called for help. A landowner found them and their dog and gave them rides on his ATV back to his house, where a warden picked them up and brought them to their vehicle, which was parked at the park.

But Stiner then drove toward the boat ramp instead of in the other direction toward Machias, Smith said.

After the women called 911, authorities used GPS coordinates from the cellphone to place the van near the boat ramp. Responders at first couldn't find it because it was dark and foggy out, and the dark-colored van was in 20 feet of water and couldn't be seen from shore or the water's surface, said Lt. Travis Willey, of the sheriff's department.

Officials summoned a volunteer diver from the Jonesboro Fire Department, who found the car about 175 feet off the boat ramp, the women and the dog inside with the doors closed and the windows up. The car was then towed out of the water with the victims inside.

Weather could have contributed to the accident, Smith said.

"It appears they went the wrong direction and drove off the ramp," he said. "If you don't know the area, in the fog and rain it wouldn't be a difficult thing to do."