Catherine Casey’s cellphone rang Friday night as she crossed into Massachusetts on Interstate 93 from New Hampshire, where rescuers had just concluded four days of searching for her husband, who had gone missing while hiking the White Mountains.
On the line was Lieutenant James Kneeland of the New Hampshire Fish and Game Department, and he had news: Casey’s husband, 70-year-old Christopher Staff of Dorchester, had been found alive.
“I said, ‘I love you, Jim,’ ” Casey said she told Kneeland.
Her brother, who was driving, turned the car around, and a little more than two hours later, at 10:25 p.m., the couple reunited in the parking lot for the Lincoln Woods trailhead. It was the same spot where Staff had started hiking the 31-mile Pemigewasset Loop at 1 a.m. Monday.
“It was amazing,” Casey said Saturday. “It was the best day of my life.”
Staff was recovering Saturday evening from dehydration and going without food, at Speare Memorial Hospital in Plymouth, where he was taken Friday night by ambulance.
He had just descended Bondcliff, a climb of 4,265 feet, Monday night when he lost the trail, Kneeland said Saturday. Officials believe Staff was looking for water, Kneeland said, and spent much of his time in the wilderness near Black Brook.
Casey contacted New Hampshire officials Monday at 11:30 p.m., about two hours after Staff was due home. Her husband is an experienced hiker, she said, who had always wanted to hike this section of the White Mountains, also known as the Pemi Loop.
During heavy rains Tuesday night, Casey said Staff took shelter under a rock. She said he heard helicopters overhead Wednesday but couldn’t reach a clearing and catch their attention.
On Thursday, Staff spent much of the day disoriented or asleep, Casey said, and unable to navigate the steep slope of rough terrain that stood between him and the trail.
He woke up Friday determined to make the climb, later telling Casey that he trained his mind on her and their son to give him strength, she said.
“He knew that if he didn’t do it on that day, he felt like his body was going to break down,” Casey said.
Staff made it up the slope, Casey said, where he encountered two young men who were camping.
One camper, a 20-year-old man from Dover, N.H., ran for help, while his friend, a 19-year-old man from Gloucester, stayed behind with Staff, Kneeland said.
“He had the obvious appearance of dehydration. He probably hadn’t eaten anything in about four days,” he said.
About 3 miles into his run, the camper from Dover met a hiker carrying a device that sends GPS coordinates to emergency officials and transmitted a message.
Rescuers, who had just concluded search activities, received the notice around 7:45 p.m., Kneeland said, and headed back into the woods.
New Hampshire conservation officers escorted Staff about 2 miles from the spot where the campers found him to an off-road vehicle waiting for him at Franconia Brook, said Allan Clark, president of the Pemigewasset Valley Search and Rescue Team, a volunteer group that looked for Staff. He was able to walk to the vehicle with assistance, Clark said.
“He survived during some very, very tough conditions,” Clark said.
Kneeland declined to identify the two campers who rescued Staff. The men were continuing their trip Saturday, Kneeland said, and couldn’t be reached.
The search for Staff was extensive.
On Tuesday, conservation officers and searchers from the Appalachian Mountain Club checked many trails in the Pemi Loop but didn’t find him. Later Tuesday, officials learned some hikers might have spotted Staff near the summit of Mount Bond on Monday evening. The mountain peak is 4,698 feet.
On Wednesday, volunteers from Clark’s organization joined conservation officers in the search by scouring drainage areas near Mount Bond and Bondcliff. The New Hampshire Army National Guard flew searchers to the summits and also conducted an aerial search, officials said, but didn’t find Staff.
The search entered its third day Thursday as officials resumed their efforts by combing drainage areas. Authorities also received calls reporting that Staff had been traveling clockwise around the Pemi Loop and had reached the summit of Mount Bond.
On Friday, searchers from six different organizations, including a K-9 team, set out looking for Staff. Their efforts concluded at 7:30 p.m., officials said. Fifteen minutes later, officials got word that Staff may have been found.
Casey said she leaned on family, including her brothers, Jack, a geologist, and the Rev. Robert Casey, a Roman Catholic priest in South Boston, for support, and she gave thanks to everyone who searched for Staff.
“There were so many people praying for Chris,” she said.
In Newton, where Staff owns a specialty cake business called The Icing on the Cake, his colleague, Paula Kirrane, said the workers were “happy Chris was found safe and sound.”
Mark Steele, a longtime friend from Salem, said he and his wife, Ruth, went to New Hampshire Thursday to look for Staff and support Casey. He said they were relieved when Casey texted Friday night with news that Staff had been found.
“I stayed with the belief that he was alive even when it looked pretty dim,” Steele said.
Laura Crimaldi can be reached at laura.crimaldi@globe.com. Follow her on Twitter @lauracrimaldi.