BIG BEAR LAKE, Calif. – Searchers took advantage of a break from stormy weather Saturday in their hunt for a former Los Angeles police officer suspected in three killings, patrolling a mountain resort town in heat-sensing copters and fanning out on foot in fresh snow even as vacationing families and weekend skiers frolicked nearby.

The stark blue skies that emerged after a Friday snowstorm allowed San Bernardino County sheriff’s choppers to fly low over the forest and SWAT teams to look for tracks and other clues that might lead to Christopher Dorner, 33, whose burned-out pickup truck was discovered Thursday in town.

Authorities suspect Dorner in a series of attacks in Southern California over the past several days that left three people dead, including a police officer. Authorities say he has vowed revenge against several former LAPD colleagues who he believed cost him his law enforcement career.

San Bernardino County sheriff’s Detective Chad Johnson said he and others were intent on finding Dorner but also looking for other telltale signs of his whereabouts.

“There’s a million clues in the mountain. You’ve just got to be patient to find them,” Johnson said.

Johnson said the foot search includes mountainous areas that are very steep and high climbs that often end in cliffs.

The search was the third full day of the massive multi-agency effort now centered on this resort town about 80 miles northeast of downtown Los Angeles. Investigators continue to analyze the truck discovered Thursday on a local road, and are trying to determine whether Dorner torched it or if it caught fire for other reasons.

Officers armed with semi-automatic weapons have been going door to door examining hundreds of vacant cabins, aware that they could be walking into a trap set by the well-trained former Navy reservist who knows their tactics and strategies.

“Christopher Dorner is probably one of the most dangerous fugitives that law enforcement has gone after in recent times,” said Clint Van Zandt, former supervisor of the FBI’s profiling unit. “The challenge is, with his law enforcement and military background, he’s very competent with weapons.”

Sheriff’s Detective Jeremiah MacKay, who began his patrol at 5 a.m. Saturday, said the operation was both massive and tactically complex.

“This one you just never know if the guy’s going to pop out, or where he’s going to pop out. We’re hoping this comes to a close without more casualties,” MacKay said.

Police said officers still were guarding more than 40 people mentioned as targets in a rant they said Dorner posted on Facebook.