SAN DIEGO — A sinkhole buckled a four-lane road today in a hilly upscale neighborhood, destroying one home and damaging five others. No injuries were reported.

Power lines fell, and 20 homes were evacuated — 10 on a hilltop and 10 on a street below, according to the San Diego Fire-Rescue Department. Seven people were inside the homes that were evacuated.

The collapse shortly before 9 a.m. left a ravine of crumpled pavement. Orange traffic cones and sections of big concrete pipes sat in the fissure slashing across the wide boulevard.

The sinkhole in the La Jolla neighborhood of million-dollar homes cut a cone shape and was about 50 yards long and 15 feet deep, a city engineering geologist, Robert Hawk, said. Six homes were damaged or destroyed and two others were in danger, but the problems appeared to be contained, he said.

“It is fairly well-defined and localized,” Mr. Hawk said.

Electricity was initially cut off to 2,400 customers but restored to 2,000 within two hours, according to San Diego Gas & Electric Co. Gas was cut off to about a dozen customers.

Holli Weld was walking her son to preschool when the street collapsed.

“It was sinking as I was walking by,” she said. “The street was sinking before our eyes.”

At least three significant hill slides have occurred in the area between 1961 and 1994, including a major failure in 1961 that destroyed seven homes under construction.

A firm hired by the city last month was in the area this week after a large section of slope on Mount Soledad began to slip, Mr. Hawk said. The city began noticing cracks on Soledad Mountain Road in July and became concerned about a landslide three or four weeks ago.

The city sent letters to residents Monday and Tuesday warning residents, and the outside firm hired by the city recommended Tuesday that four homes be evacuated, Mr. Hawk said.