LAS VEGAS — A high pressure system hanging over the West this weekend is expected to bring temperatures extreme even in a region used to baking during the summer.
Notoriously hot Death Valley's forecast could touch 129 degrees, not far off the all-time world-record high of 134 logged there July 10, 1913.
The National Weather Service called for 118 in Phoenix, and 117 in Las Vegas on Sunday — a mark reached only twice in Sin City.
"It's brutal out there," said Leslie Carmine, spokeswoman for Catholic Charities, which runs a daytime shelter in Las Vegas to draw homeless people out of the dangerous heat and equip them with sunscreen and bottled water.
While the Southwest boasts the most shocking temperatures, the heat wave is driving up the mercury all over the West. Western Washington — better known for rainy coffee shop weather — should break the 90s early next week, according to the weather service.
Dry southern Utah is forecast to reach higher than 110 degrees, and northern Utah — which markets "the greatest snow on Earth" — is also expected to see triple digits.
The heat wave is "a huge one," National Weather Service specialist Stuart Seto said. "We haven't seen one like this for several years, probably the mid- to late 2000s."
The system's high pressure causes air to sink and warm, drawing down humidity.
"As the air warms, it can hold more moisture, and so what that does is take out the clouds," Seto said.
The hottest cities in the West are taking precautions to protect vulnerable residents. Police are pleading with drivers not to leave babies or pets in their car, and temporary cooling stations are welcoming homeless people and seniors hesitant to use the air conditioning.
Officials said extra personnel have been added to the U.S. Border Patrol's Search, Trauma, and Rescue unit as people illegally crossing the border from Mexico into Arizona could succumb to exhaustion and dehydration.
Several bodies of immigrants have been found in the last week in Arizona. 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.
At low-lying Lake Mead, which straddles the Arizona-Nevada border and is anticipating 120 degrees this weekend, rangers are positioned at trailheads to discourage visitors from hiking.
Earlier in June, a group of Boy Scouts hiking in the Colorado River canyon fell prey to soaring heat. Four teenagers and an adult had to be rescued, while a 69-year-old Scout leader died.
"We don't want a repeat of the tragedy we had a few weeks ago," Lake Mead spokesman Kevin Turner said.