Firefighters battling a stubborn wildfire northeast of Los Angeles were expecting help Tuesday from cooler temperatures and calmer winds.

As the dramatic blaze entered its fourth day, most of the more than 1,000 people evacuated from their homes at the foot of the rugged San Gabriel Mountains have been allowed to return. On Tuesday, public schools in the community of about 11,000 residents were scheduled to reopen.

The 538-acre blaze burned dangerously close to homes early Monday, but firefighters stood their ground and turned the flames back.

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No homes have been lost in the blaze in the foothill suburb of Sierra Madre, 15 miles northeast of Los Angeles. The fire was 21 percent contained Monday.

Helicopters and airplanes bombarded the fire with water and retardant drops Monday while firefighters labored in temperatures in the 90s. Nearly 700 firefighters were on the lines.

Temperatures were expected to reach the mid 70s Tuesday, with high humidity and little wind.

Four firefighters had minor injuries — a bee sting, a strained knee, and two cases of heat exhaustion, authorities said. A small outbuilding was destroyed.

On the Scene: Fox News' Adam Housley Covers Fires in Sierra Madre.

The cause of the blaze remained under investigation.

The fire broke out Saturday afternoon in a popular hiking area as unseasonable extreme heat and low humidity set in over Southern California. By late that night it was a bright orange line descending like slow-moving lava down the steep mountainside, triggering evacuations along the interface between the city and wilderness.