Man, 4 Teens Die in Crashes on 2 Freeways Bound in Fog : Traffic: Two young men are hospitalized after fatal accident in Burbank. Officials say weather may have impaired visibility on the road.

Five people--four of them teenagers--were killed in two traffic accidents early Sunday after thick fog set over the San Fernando Valley, authorities said.

In Burbank, three young men were killed after their car crossed over the eastbound lanes of the Ventura Freeway, careened over an embankment east of Bob Hope Drive and barreled into a tree, said Officer Gary Goldenberg of the California Highway Patrol.

In addition, two 18-year-olds in the car were injured and taken to County-USC Medical Center, a dispatch center spokesman said. One was in critical condition with multiple internal injuries and the other was in fair condition with bruises and a fractured leg.

The five youths were all wearing seat belts in the 1 a.m. accident, the spokesman said. The county coroner’s office identified the three youths killed in the crash as Piero Fernandez, 19, of Glendale; Christopher Bay, 17, also of Glendale; and Victor Alvarez, 17, of Yucaipa. They were declared dead at the scene.

Goldenberg said it was unknown whether fog caused the crash. But weather forecasters said the fog, which moved in after sunset Saturday and thickened as temperatures dropped, decreased visibility throughout the night.

By early morning, the fog was so thick in the Burbank area that motorists probably could “hardly see down the street,” said Curtis Brack, a meteorologist with WeatherData Inc., which provides forecasts for The Times.

In Mission Hills, an hour after the Burbank crash, Jose Lopez Jr., 23, and his 14-year-old passenger, Octavio Cardinas, were killed after their sport-utility truck drifted across the westbound lanes of the Ronald Reagan Freeway at the northbound Golden State Freeway transition, struck an embankment and rolled over several times, said CHP Sgt. Steve Munday.

Lopez, of Sylmar, was not wearing a seat belt and was ejected from the car and thrown 40 feet across the freeway, Munday said. His teenage passenger had a seat belt on but was crushed inside the car, officials said.

Munday said fog may have contributed to the accident.

The National Weather Service issued a dense-fog advisory for Southern California coastal valleys from pre-dawn to about 9:30 a.m. Sunday.

Officials at Burbank and Van Nuys airports said the fog made pilots and flight crews more cautious but did not lead to serious problems.

Some early-morning commercial flights at Burbank Airport were delayed briefly, but operations were back to normal by about 8:30 a.m., said airport spokesman Tony Snow.

Brack said weather conditions in the region are likely to cause dense night and early-morning fog for several days. The fog is expected to burn off during the day but to return once the sun goes down, he said.