Authorities in Boulder, Colorado, warned some residents to prepare to evacuate Thursday as winds gusting as high as 50 mph threatened to drive a raging wildfire out of the hills and into city limits.

The Fourmile Canyon fire already had charred nearly 6,400 acres of countryside and destroyed 169 homes west of Boulder by mid-morning Thursday.

High winds that could whip the fire toward the city were expected to kick up Thursday evening and last throughout the night, forecasters predicted.

FULL STORY