A strike team composed of firefighters from Alameda County and the cities of Oakland, Fremont and Hayward has returned to the Bay Area after two weeks battling the massive Bootleg Fire in Oregon.

The team worked 12-hour shifts for two weeks and experienced erratic fire behavior in the Fremont-Winema National Forest, including a pyrocumulonimbus cloud that created its own weather and extreme conditions, the Alameda County Fire Department said Sunday on social media.

Crews said the fire sounded like a freight train and could be heard from miles away.

More than 2,100 personnel are currently battling the Bootleg Fire, burning northeast of Klamath Falls, Oregon, state officials said.

The fire is the largest blaze in the U.S., has scorched 410,000 acres and is 53 percent contained, according to an update Tuesday from fire officials.

The East Bay team of firefighters helped fill an Emergency Management Assistance Compact interstate agreement, officials said.

Fire crews from California prepare a rig for its next deployment at the Bootleg Fire. (Photo courtesy of Alameda County Fire Department/Twitter)