BIG BEAR LAKE (  —  The stubborn Lake fire continues to rage, officials said Sunday.

Authorities said about 1,900 firefighters were working around the clock to battle the blaze.

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More than 17,050 acres have burned. As of about 6:10 p.m. Sunday, the fire is only 19 percent contained, officials reported.

Firefighters on Sunday also had to deal with extreme temperatures often pushing or exceeding triple digits. Several heat advisories were issued. They were expected to expire at sundown.

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Five-hundred structures are threatened.

The Forest Service says heavy smoke is being pushed into residential areas by strong and sustained winds in the area.

Officials said Highway 38 is closed from the east side of Angelus Oaks to Lake Williams, Hiking Trails into the San Gorgonio Wilderness Area are also closed. Pacific Crest Trail is closed from Whitewater Preserve to Onyx Peak.

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The fire was first reported just before 4 p.m. last Wednesday.