Technical Rescue Sonar Tool Finds Remains Of Lake Palmdale Boater

PALMDALE, CA — One week ago, the Los Angeles County Fire Department and Sheriff's Department searched Lake Palmdale for a missing man. Using sonar technology as one of their search tools, technical rescue crews found the man in the depths of the murky water within 24 hours.

Robert Lewis Mercer, 34, a Lancaster resident, was reported missing Wednesday, Feb. 5, officials said.

Witnesses on the shore of Lake Palmdale called 911 to report Mercer's empty boat floating in the middle of the remote lake, Los Angeles County Fire Department Chief Fernando Boiteux told Patch. Emergency responders did a shore search but were unable to find Mercer.

The Los Angeles County Fire Department lifeguards were called to the scene to help search the vast lake. Divers arrived by helicopter while technical rescue operators drove 70 miles from the coast.

After a length of time, it was suspected he drowned in the lake, according to Boiteaux. The technical rescue of the man's remains was put into play.

"The water was deep, with limited visibility," Boiteux said. With depths between 20 to 40 feet and temperatures at or below 50 degrees, the department looks to technical rescue "tools" to help narrow the search territory. One of those tools is Sonar EMILY.

The remotely driven sonar boat was driven across the lake to determine what lay below the surface. Sonar EMILY is just one of the "technical gadgets" deployed in the search, Boiteux said.

In this case, as the day wore on with only six divers airlifted to the scene, the 586-acre artificial lake fed by the California Aqueduct was too big to search without using such a sonar tool.

"Sonar technology enables the search teams to view areas that are dangerous to humans," Boiteux told Patch. "You avoid putting a diver in an area that could be risky."

The water was deep and frigid.

"That limits the length of time divers can be underwater," he said.

All eyes were trained on the water as the bright red sonar boat did its work, recording what lay beneath the surface. Before sundown, Sonar EMILY got a "hit," or an image that is different than the surroundings, he said.

"Due to the lack of light, the Sheriff said the dive would continue the following day," he told Patch. As the search transformed from rescue to recovery, the sheriff's department released the fire department and took over the investigation.

LA County Fire shared the "hit" location Sonar EMILY found with the Sheriff's Department, he said. The following day Mercer's remains were verified and recovered by the LASD sonar and dive operation team.

The Los Angeles County Coroner confirmed that the body discovered in Lake Palmdale was indeed Mercer.

Boiteux added that before a person boats or swims alone, always alert someone to your whereabouts, and check that the conditions of the water are safe. Always swim near a lifeguard, he said.