The Grand Canyon is about to become slightly more literal in its description as a 'hole in the ground,' with the US National Weather Service issuing an extreme heat watch for the area starting Monday. Temperatures are expected to exceed 100F (37.7C), and could climb as high as 112F (44.4C) in lower parts of the canyon, according to the NWS office in Flagstaff, Arizona. The alert, published Saturday, runs from 10am local time Monday through 7pm Tuesday.

This is not a drill, nor is it a playful suggestion to bring an extra water bottle. The NWS warns of 'dangerously hot conditions' below 4,000ft, with daytime temperatures ranging from 97F (36.1C) at Havasupai Gardens to a toasty 111F (43.8C) at Phantom Ranch. The agency's Flagstaff office noted that such extreme heat watch notices are 'reserved for only the hottest days of the year' and are issued when temperatures could rise to dangerous levels. 'Most individuals will be at risk for heat-related illnesses without effective cooling or adequate hydration, especially with prolonged outdoor exposure,' they added, presumably while sweating in their own office.

The warning follows a string of recent heat-related deaths in the park that suggest 'don't hike during the hottest part of the day' is not yet a universally accepted life hack. On Friday, the National Park Service reported two separate heat-related incidents on June 12 and June 16 that resulted in three deaths: a 72-year-old man on the South Kaibab Trail, and a 67-year-old man and 68-year-old woman on the North Kaibab Trail. 'Despite rapid response and aerial support, all three individuals were found deceased when responders arrived,' the park service said, adding that an investigation into the latter incident is ongoing. Earlier this month, an 18-year-old man also died from heat-related symptoms in the park. The park service noted that 'hiking in Grand Canyon can be a challenge for anyone, especially during the heat of summer,' which is a bit like saying 'the desert can be dry.'

But wait, there's more heat elsewhere! Evacuation orders have been issued for communities between Sedona and Forest Highlands due to the Pocket fire near Sedona. Extreme heat watches are also in effect for parts of Oregon from Monday through Tuesday evening, and portions of California from Tuesday evening through Thursday. Texas is bracing for 'triple-digit heat' from Sunday into early next week, according to the NWS office in San Angelo. Heat advisories are currently active for parts of Alaska, Puerto Rico, Florida, Texas, Arkansas, Oklahoma, and New Mexico. And just to add a layer of sports-related irony, the US is co-hosting the FIFA World Cup, and a Guardian analysis found two first-round matches were played at heat levels that a football players' union says should trigger game delays or postponements. So, if you're planning a Grand Canyon hike, maybe wait until, say, November.