"The wind is beginning to pick up," she wrote in her blog from the Indian Ocean on Wednesday. "It is back up to 20 knots and I am expecting that by midnight tonight I could have 35 - 50 knots with gusts up to 60 so I am off to sleep before it really picks up."
By the next morning, the Southern California girl – who once had hoped to become the youngest sailor to circle the globe solo without stopping – was lost at sea.
A rescue effort was launched Thursday, but the soonest any craft could arrive would be 40 hours, and an air rescue was stymied by her remote location, her parents wrote on her blog.
"Abby has all of the equipment on board to survive a crisis situation like this," says the note signed by her father Laurence, her mother Marianne and "Team Abby." "She has a dry suit, survival suit, life raft, and ditch bag with emergency supplies. If she can keep warm and hang on, help will be there as soon as possible.
The drama started early Thursday morning when Sunderland's satellite phone went dead during a conversation with her family. At the time, her 40-foot boat, "Wild Eyes," was being tossed around by 30-foot swells during a storm halfway between southern Africa and Australia.
Search and rescue personnel from France, Australia and the United States picked up a signal from one of Sunderland's emergency beacons – which appeared to have been manually activated – about an hour after her phone went dead. Minutes after that, another emergency beacon signal was detected.
Sunderland left on her voyage on Jan. 23 from Marina del Rey, Calif., just months after her brother Zac returned from his own solo circumnavigation by sailboat at age 17. Abby ran into technical problems in April, forcing her to put her journey on hold while she repaired her boat.
On May 15, a 16-year-old Australian girl set sailing record after circumnavigating 23,000 miles in 210 days. Although Sunderland was no longer a contender for the record, she decided to push on with her odyssey in "Wild Eyes" and left Cape Town, South Africa on May 21.