California - Curtis Whitson has two strangers to thank for his family being alive today. Two brave hikers plucked a lime green bottle from a river and alerted authorities about the SOS message they found inside.

Whitson, his 13-year-old son and girlfriend, Krystal Ramirez, had decided to spend Father’s Day weekend backpacking the Arroyo Seco River.

They spent their days boulder-hopping and floating the river on inner tubes, and their nights sleeping under the stars, bundled in lightweight mummy bags, with mesh bags over their heads to keep bugs at bay.

Throughout the trip, the family’s goal was to reach the Arroyo Seco narrows. After two and half days of lugging 50-pound packs, the family reached the narrows, a spot in the river surrounded by solid rock up to 40 feet high on each side. But the water currents were too strong for them to safely pass through.

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

Whitson spotted a lime green Nalgene water bottle and carved ‘HELP’ into the durable plastic exterior. “With one lucky toss, it went right over the waterfall,” Whitson said.

Sometime after midnight the trio was awakened by the sound of a California Highway Patrol helicopter overhead.

Whitson said he was told two men found the bottle with the family’s note, floated down to the trailhead, then hiked a couple of miles and reached the campground where they alerted the camp host.