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Highway 18 closed: Hundreds of firefighters jump on fire near Crestline

About 400 firefighters in San Bernardino County are battling a 15-acre fire that erupted Thursday night when a pickup truck plunged off Highway 18 near Crestline and burst into flames.

San Bernardino National Forest spokesman John Miller says the driver escaped with only minor injuries. One firefighter suffered an apparently broken ankle.

No homes are threatened but Highway 18 remains closed.

The blaze is being pushed by 30-mph winds and the National Weather Service has issued red flag warnings for extreme fire conditions in the mountains, valleys and coastal slopes. The warning continues until this evening because of a high-pressure ridge will keep things hot, dry and gusty.

UPDATE 9:28 a.m. Highway 18 is scheduled to re-open at 10 a.m. The number of firefighters there does not necessarily reflect the seriousness of the fire, but concern about the conditions.

"I don’t want to say we’re worried, but we’re just concerned about it and that’s why we have a lot of folks out here and that’s why we’re working as hard as we are," said John Miller, a spokesman for San Bernardino National Forest Branch of the U.S. Forest Service.

More on the fire from NBC LA below: