Some Phoenix hiking trails to be restricted in extreme heat A pilot program is now in place and select city hiking trails will be restricted during periods of extreme heat. Author: Associated Press Updated: 6:15 PM MST July 16, 2021 PHOENIX — The Phoenix Parks and Recreation Board has approved a pilot program to restrict select city hiking trails during periods of extreme heat. The pilot program will run from July 16 to September 30. During that time, Camelback Mountain's Echo Canyon Trail and Cholla Trail and all trails associated with Piestewa Peak Trailhead in the Phoenix Mountains Preserve will be closed from 11 a.m. to 5 p.m. on days when an excessive heat watch is in effect.