Firefighters warned people in a Glendale neighborhood that helicopters were drawing water from neighborhood lakes to fight a fire Thursday. The Thunderbird Fire started on Thunderbird Mountain in Glendale. It grew to about 30 acres as of Thursday afternoon. The fire was moving north and northeast with a moderate rate of spread. Nearby residents were asked to stay inside and report spot fires. The Thunderbird Fire is near 59th Ave and Pinnacle Peak within the Thunderbird Conservation Park, according to fire officials. The fire spread moderately on Thursday morning. Helicopters took water from nearby neighborhood lakes and dropped it on the fire. The cause of the fire was not immediately known.