Much of the western United States remains in the grip of a heat wave which is expected to continue for several more days.
The tinder-dry conditions are believed to have contributed to the extreme conditions which claimed the lives of a group of 19 firefighters, attempting to contain a wildfire at Yarnell Hill, 135km north of Phoenix, Arizona.
The fire, which is believed to have been caused by a lightning strike, spread rapidly across eight square kilometres, fuelled by ongoing drought, high temperatures, very low humidity and winds of 30 to 50kph.
Elsewhere, at least one person is known to have died as a result of heat-related illness. Many others have been treated, including six half-marathon runners at a race in Southern California.
Temperature records have been broken in some states. Las Vegas, Nevada hit a high of 47.2 Celsius on Sunday, tying the desert city’s all time record, only equalled in 2005 and 1942. The month of June was the warmest ever recorded in ‘Sin City’.
On Saturday, Phoenix hit 48.3 Celsius, the fourth hottest day ever recorded in the city in more than 110 years.
There had been talk of the possibility of a record being set at the world’s hottest, officially recorded location, Death Valley, California. Although the all-time record of 56.7 Celsius set back on 10 June 1913 was never under threat, the desert site did record the highest June temperature.
A high of 53.9 Celsius was reached on Sunday although it will take several months of analysis before it can be confirmed officially.
The heat has spread as far north as Washington and Oregon with Portland recording temperatures 10 degrees above the seasonal average of 24 Celsius.
Although these northern states are expected to cool off towards the end of the week, much of California, Nevada and the Four Corner States will remain hot and dry with well above-average temperatures.