It was about 9:30 a.m. Monday, Nepal time, and the Long Beach teenager was waiting below a base camp on the side of Mt. Everest for a helicopter to take her trekking group, including her father, to Katmandu.
Before the satellite phone crackled out for good, Larson, a 2006 honors graduate at Long Beach Polytechnic High School who deferred her freshman year at Stanford University by a year to train and climb Mt. Everest, added a few understated thoughts.
"I feel really great, you know? I'm happy," she said, laughing softly as she stood alone outside a lodge in Lobuche, below the camp. "I'm happy to be going back to a real bed and a hot shower tonight. I guess I'm kind of relieved that things went well."
Larson and her father, David, 51, reached the top of Mt. Everest on Thursday morning, Nepal time. She's the youngest American ever to reach the summit.
The Larsons also become, perhaps, the first father-daughter team to conquer the so-called seven summits, the highest peaks on each of the seven continents.
They have climbed mountains as a team since Larson was a middle school student lugging along algebra homework and a plastic oboe to stay in practice during the rigorous weeks involved in such ascents.
Describing the difficulty of the climb, Larson said the altitude drains all appetite; after gobbling down a chocolate bar, she subsisted for several days only on water to ward off dehydration. The temperature on the snowy peak reached "probably 30 below? I'd say 30 below," she said.
"Your whole body is completely covered with [goose] down; your face is covered with your oxygen mask and goggles," she said. "Temperature-wise, we were lucky. We had beautiful weather on summit day. There was no wind."
Still, the conditions on the summit were daunting.
"On summit day, we wore everything," she said, referring to the garments they had packed to keep warm.
But on the descent from the peak, she said, "We actually took off some layers." The party included climbers who have previously climbed mountains with her and her father, an anesthesiologist at Long Beach Memorial Medical Center.
The Larsons arrived at the mountain's base last month, and Samantha began blogging to http://www.samanthalarson.blogspot.com . She had to telephone her last two entries via her mother and brother, who live in New York.
Late Sunday night, Larson said she still had no Internet access and had not been able to resume her blog entries, which had elicited dozens of comments from strangers all over the country cheering her on.
She hopes to fly home Wednesday and rest for several days before her brother's graduation Saturday from Bard College in New York.
Asked about the worst part and the best part of her life-changing Mt. Everest climb, Larson paused to think.
"The worst part was when we were coming back down from Camp 4," she said, as the phone grew faint and then disconnected.
She will have to tell the world herself about the best part.