A wildfire that broke out in the Angeles National Foreston Sunday forced the evacuation of thousands of visitors and sent a huge cloud of smoke that could be seen from throughout the Los Angeles basin.

The fire broke out near a campground around 2:30 p.m. and spread quickly, fueld by dry brush.

It forced the evacuation of campgrounds that typically attract up to 12,000 visitors on Labor Day holiday weekend, as well as rehabilitation centers and the private community of Camp Williams Resort above the city of Glendora, forest spokeswoman L'Tanga Watson said.

"We got most folks out along the recreational area," Watson said.

CBS News correspondent Bill Whittaker reports the fire forced the evacuation of thousands of people from a mobile home park and local campgrounds. One firefighter and two others required medical assistance on Sunday as a result of the blaze, which had charred at least 3,600 acres by nightfall. It was not immediately clear what the three victims were treated for. (MORE)