Washington, Jul 4 (IANS): The US National Park Service (NPS) confirmed that a woman has died while hiking in the Grand Canyon as temperatures soared amid an ongoing heat wave.

In a statement, the NPS saidsaid that at around 6.30 p.m. on Sunday evening, a park ranger received a report about a hiker who was in distress in the Tuweep area of Arizona's Grand Canyon National Park, ABC News reported.

Officials said the 57-year-old woman was on an 8-mile hike in the remote area of the park when she lost consciousness.

"A ranger arrived on scene at approximately 1 a.m. on July 3 (Monday) and pronounced the hiker deceased," the statement added.

On Sunday, the temperature at Tuweep was over 37 degrees Celsius, according to the NPS.

At Phantom Ranch, southeast of the site and near the Colorado River, it reached 45 degrees.

Parts of the Grand Canyon are under an excessive heat warning through Wednesday, ABC News quoted NPS officials as saying.

Park rangers recently told hikers and backpackers to prepare for extremely high temperatures in the weeks ahead.

About 35 million Americans are on alert for dangerously high temperatures, with the centre of the heat dome over the West.

On Monday, temperatures reached 45 degrees in Phoenix and Palm Springs, 44 degrees in Las Vegas and 48 in Death Valley.

Eight southern states from Texas to Georgia, the heat index on July 1 ranged from 40 to 46 degrees.