AAA Jun. 29, 2013 5:56 AM ET AP PHOTOS: Images of the western US heat wave By The Associated Press By The Associated Press A jet looks like it is melting into the runway as it is distorted by the heat waves rising up from the north runway at Sky Harbor International Airport, Friday, June 28, 2013, the hottest day of the year so far. Elephants at Utah's Hogle Zoo are cooled off with a water hose Friday, June 28, 2013, in Salt lake City. Michael Jackson impersonator Juan Carlos Gomez drinks some water as he takes a break from posing for photos with tourists along The Strip, Friday, June 28, 2013 in Las Vegas. Bess, an orangutan at the Phoenix Zoo, keeps cool under a wet sheet and a hose, Friday, June 28, 2013 in Phoenix. Dangerously hot temperatures are expected across the Arizona deserts throughout the week with a high of 118 Friday. A heat wave across the western U.S. was so punishing that rangers took up positions at trailheads at Lake Mead in Nevada to persuade people not to hike. Dogs were at risk of burning their paws on scorched pavement, and airlines kept close watch on the heat for fear that it could cause flights to be delayed.