A family stranded near a California waterfall Father’s Day weekend was rescued thanks to their message written and scratched into a bottle.

Curtis Whitson, 44, was rescued Father’s Day weekend after he became trapped near California’s Arroyo Seco Canyon waterfall with his girlfriend, Krystal Ramirez, and 13-year-old son, Hunter. They had gone out to backpack through Pfeiffer Big Sur State Park for the weekend before ending at the park’s campgrounds. The trek had gone fine until they arrived at the waterfall, which Whitson had scaled down safely seven years earlier. However, they did not have a rope to scale and the current was too strong for them to safely descend.

“My heart sank when I realized the volume of water was just too dangerous to make rappelling down possible,” Whitson told the Washington Post.

The group first formed an SOS message using rocks before Whitson wrote a message using a bar order pad Ramirez had brought with them to keep score for games they played. He then stuffed the message into a green water bottle they found nearby, scratched “help” into the bottle twice, and sent it down river.

“It was a little scary,” Whitson said. “We hadn’t seen a single soul the entire trip.”

“6-15-19 We are stuck @ the waterfall get help please,” Whitson wrote on the paper.

The bottle continued down river until it was discovered by two unidentified hikers later that day. The hikers then passed the message along to the host of the nearby campgrounds. It was then passed along to California Highway Patrol, who began a mass search effort of the area. A CHP Air Rescue found the group around midnight and told them to stay put and stay warm while crews worked their way to them. Whitson, his son, and Ramirez were rescued early the next morning.

“As you can imagine, they were very happy to see us,” pilot Joe Kingman told the Washington Post. He added it was the first time he’d seen anyone had used a bottle to send a rescue message in his 23 year career.