Investigators determined that the fire began near Seneca Pond, an area popular with runners and teenagers in this resort area along the California-Nevada state line. They also said they were close to identifying its cause. An announcement on that was expected later Tuesday.

Authorities have said they believe the fire was caused by some kind of human activity, but U.S Forest Service officials said there was no indication it was intentionally set.

The forest here was so dry that a discarded cigarette butt or match could easily have ignited the fire, Forest Service spokeswoman Beth Brady said. The area was also dotted with the remnants of illegal campfires, she said.

Experts have said California and the rest of the West are entering what could be a long and dangerous fire season after one of the region's driest winters on record. They warn that years of logging, development and forest mismanagement have left the Tahoe area particularly vulnerable to catastrophic wildfires.

"Lake Tahoe Basin is probably an extreme example, but very similar conditions exist throughout the Sierra Nevada," Forest Service spokesman Matt Mathes said. "It can happen literally anywhere at any moment."

In Meyers, the charred landscape included manicured driveways leading to metal garage doors that were still standing amid the ruins of destroyed homes.

Hartzell's sister-in-law, Ruth Orozco, a nurse, also lost her home but was able to escape with her two dogs and one cat.

"I can't believe it's all gone," she said, breaking into tears.

Concerned about looting, dozens of sheriff's deputies and California Highway Patrol officers roamed the burned neighborhoods, ensuring that only those who lived in the area were allowed in. Cars lined up to pass through an elaborate checkpoint where each vehicle's window was marked with white shoe polish to designate the street number of the home it was allowed to visit.

"It was eerie and awkward. You could see the expressions on everyone's face," said Lindsey Douglass, 22, after she made her way through the line of more than 30 waiting cars.

Concerns about downed power lines and other hazards forced some homeowners to delay their return until later this week.