BBC News

In pictures: Heatwave hits western US

image captionAreas in the west of the United States are baking under an extended heatwave, which has seen temperatures rise to about 50C in some places. Here a heat haze is visible over Los Angeles.
image captionTowns and cities, like Mesa in Arizona, have begun operating cooling and misting stations so residents can have some respite. People have been warned to be on the alert for signs of dehydration and heatstroke.
image captionIn Phoenix, Arizona, the mercury hit nearly 47C on Friday, prompting many people to take to any measures to cool down.
image captionIn zoos across the region, keepers have been hosing down the animals to keep them cool, even those well-adapted to the heat like these elephants at Utah's Hogle Zoo.
image captionJai the tiger, at Phoenix Zoo in Arizona, was among the animals given frozen fish, to help them stay cool.
image captionThe heat means a change in working patterns if projects are to stay on schedule - this construction crew in Queen Creek, Arizona, were beginning work early in the morning to beat the heat of the day.
image captionIn the desert city of Las Vegas, street performers - like this Michael Jackson impersonator - took what measures they could to stay in the shade.
image captionThough most large aircraft are able to take off in temperatures of up to 52C, airlines said they would be monitoring conditions closely to ensure safety - some delays are expected.
image captionIn Death Valley, California, the temperature reached nearly 53C on Friday and was still expected to rise - all eyes are on whether the desert will break its own record for the hottest temperature ever recorded on Earth of 57C, almost 100 years ago.
image captionAn extreme heat warning is in place in the national park, with visitors advised to travel in the cooler part of the day and to carry emergency supplies with them, in case their vehicle breaks down.
image captionWeather forecasters say the heatwave has been caused by a high-pressure system stuck over the area, and is expected to stay throughout the weekend.