The heat wave that is gripping the western U.S. is one of the worst in years, with desert locations in the Southwest seeing temperatures approach 120 degrees.

“It’s brutal out there,” said Leslie Carmine, spokeswoman for Catholic Charities, which runs a shelter in Las Vegas to get homeless people out the heat.

But just how bad is it? To give some perspective on the heat, here are five facts about the punishing nature of the heat wave:

5. Death Valley

Heat Wave in Western U.S. Is One of the Worst on Record

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The desert valley in California will see temperatures approach 130 degrees. The hottest temperature ever recorded on Earth occurred in Death Valley with a reading of 134 degrees, almost 100 years ago to the date in 1913. The park is dotted with locations such as Furnace Creek and Dante’s View, and officials are urging people to exercise extreme caution during the heat wave. But sweltering heat is often a big draw for visitors to Death Valley National Park – especially tourists from Germany and France – with hotels already booked solid during the hotter months of July and August.

4. No Escape

Heat Wave in Western U.S. Is One of the Worst on Record

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The easiest way to beat the heat in cities like Phoenix is to flee the desert for higher-elevation mountain cities such as Flagstaff, Sedona and Prescott which typically are much cooler. But there won’t be much of a break from a heat during this hot spell. Flagstaff could approach the record Saturday of 97 degrees, and Sedona could be in the 110 range.

3. Be Careful

Heat Wave in Western U.S. Is One of the Worst on Record

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As if temperatures nearing 120 degrees weren’t bad enough, it’s even hotter yet inside cars and on concrete and asphalt roads and sidewalks. It can get to 200 degrees on asphalt during peak summer temperatures, presenting all sorts of hazards. Drivers should keep pets and children out of locked cars, and a person who suffers a fall on a sidewalk or a street could end up in the burn unit.

2. Airlines

Heat Wave in Western U.S. Is One of the Worst on Record

AP.

Bigger jetliners can handle temperatures around 126 and 127 degrees, but airlines this weekend will be closely monitoring the conditions and smaller planes may have flights delayed. When the temperature gets real hot, the air becomes less dense and changes liftoff conditions.

1. The Border

Heat Wave in Western U.S. Is One of the Worst on Record

AP.

Immigrants are constantly crossing the border in Arizona regardless of the season — sometimes with deadly consequences as they succumb to exhaustion and dehydration. At least seven bodies of immigrants have been found in the last week in Arizona, and agents in the Tucson sector rescued more than 170 people from the desert during a 30-day stretch in May and June when temperatures were even lower than expected in the coming days.

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    The Associated Press contributed to this report.