Here is the story from Fox:

LOS ANGELES — A major portion of Los Angeles (search) lost power Monday afternoon.

Outages were reported from downtown to the coast and north into the San Fernando Valley (search).

The Los Angeles Department of Water and Power did not immediately have an explanation for what happened.

A spokeswoman for the Los Angeles Police Department (search) said the Department of Water of Power was investigating the source of the outage. Terrorism was not suspected, according to Sgt. Catherine Plows, though the department went on "full tactical alert," meaning no officers were allowed to leave duty.

Traffic was snarled at intersections throughout the city when stoplights went dark.

Fire officials said they received reports of people stuck in elevators and traffic was snarled at intersections throughout the city when stop lights went dark. Some neighboring cities also were affected.

The weather did not appear to be a factor; skies were overcast in the region.

Stephanie McCorkle, spokeswoman for the California Independent System Operator, said grid managers were watching the outage closely, but had no additional information.