YARNELL, Ariz. (AP) - A fire information officer says 19 firefighters are unaccounted for while battling the Yarnell Hill Fire.
Mike Reichling told the Arizona Republic that 20 firefighters were involved in a "serious incident."
The newspaper reports that one of the firefighters has been located.
The Yavapai County Sheriff's Office has notified residents in the Peeples Valley area and in the town of Yarnell to evacuate.
Earlier, the fast-moving fire prompted evacuations of 50 homes in the Buckhorn, Model Creek and Double A Bar Ranch areas about 85 miles northwest of Phoenix.
The Red Cross said opened a shelter at Yavapai College in Prescott.
The Yarnell Hill Fire now covers nearly 2,000 acres, according to the newspaper.
The fire started Friday but picked up momentum Sunday as the area experienced high temperatures, low humidity and windy conditions.
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