For the rest of the holiday weekend, Posytan and his family searched frantically for their dog.
Sympathetic U.S. Bureau of Land Management and Forest Service rangers, along with Border Patrol agents, kept a lookout for Chelsea as they patrolled the dunes area.
Posytan posted "lost dog" notices on every available surface.
By sunset Sunday evening the family, realizing the desert darkness made further searching pointless, drove home to La Mesa, crying every mile of the way.
"Chelsea is part of our family — she is absolutely a member of our family," Posytan said. "We'd do anything to have her back with us."
Tom Sharkey, assistant dunes manager for the BLM's El Centro field office, said some 15 dogs were reported missing in the dunes area over the Thanksgiving break.
"There is a real problem with people bringing their dogs with them to the dunes at this time of year. Usually the dogs are coming from a totally different environment. These are dogs used to living in an urban setting and they become easily confused in a desert setting," he said.
Sharkey added large crowds, excessive vehicle noise, bonfires and firecrackers were additional stressors that panicked many dogs.
With New Year's Eve at the dunes coming up, Sharkey is concerned there will be more stories like the Posytans'.
"I urge people to leave their dogs at home, or failing that, make sure they have their animals on a leash or contained in a portable kennel," Sharkey said.
The missing dog is 12 years old but looks younger. She is a mixed breed but basically looks like a German shepherd with a light gray muzzle. She was wearing a red collar and address tag and is extremely friendly.
Chelsea's family members say they'll be grateful for any information on the fate of their dog, even if it does not lead to her recovery. There is a reward offered.
"It's the not knowing that's the worse thing about all this," Posytan said tearfully.
The Posytans can be reached at (619) 698-5881 day or night.
>> Staff Writer Jennifer Ralton-Smith can be reached at 337 3442 or email@example.com