LOS ANGELES >> Cooler temperatures and higher humidity levels are helping firefighters advance against a California wildfire that scorched San Fernando Valley hills and forced thousands to evacuate from their homes.

Fire officials said today the blaze that burned 12 square miles is 41 percent contained.

In all, the fire damaged or destroyed 32 structures. A man went into cardiac arrest and died when the fire broke out late Thursday.

The cause of the fire was under investigation and fire officials said they were looking into a report by a witness that flames were seen at the base of a power transmission tower.

Southern California Edison told the Los Angeles Times it did not de-energize any power lines in the fire area and cautioned it was too early to say what caused the blaze.