BANNING, California (CNN) -- Firefighters have finally gotten the upper hand on two fires in Riverside County in Southern California that blackened swaths of brushlands and led to two deaths.

Both fires are 100 percent contained as of 9 p.m. EDT Wednesday; full control is expected by Saturday, according to California Department of Forestry officials.

The fires ravaged nearly 30,000 acres of hilly brushland with an estimated loss of $925,000 in structural damage.

The cost to fight the fires is estimated at nearly $2 million. There are 1,945 firefighters engaged in the operation.

One firefighter was killed when his air tanker, a twin-engine single-seat Grumman S-2, crashed Monday afternoon while attempting to drop fire retardant on the flames.

The second firefighter died when he suffered a heart attack while trying to save a house that was in the line of a brushfire.

The fires, which began Monday morning, have destroyed five structures including one mobile home and one house. The roof of another home was destroyed.

Weather conditions that had hindered firefighting efforts have now taken a turn for the better. The strong offshore winds that fanned the flames have died down. Cooler temperatures and increased humidity are expected throughout the week.

The cause of the fires is still under investigation.

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