Visitors to Grand Canyon National Park are being warned about extreme heat early next week after the U.S. National Weather Service issued an extreme heat watch.

Visitors to Grand Canyon National Park are being warned about extreme heat early next week.

Federal officials say three hikers have died from apparent heat-related illnesses in the Grand Canyon.

An 18-year-old hiker died on Grand Canyon's Bright Angel Trail in 109-degree heat. Now officials warn extreme temperatures can overwhelm healthy hikers.

A hiker died last week, after suffering heat-related symptoms while attempting a strenuous hike through the Grand Canyon, according to the National Park Service. Park officials said rangers received...