Punishing heatwave expected across the US south-west this weekend

Millions across the US south-west are bracing for a weekend of sweltering heat as forecasts threaten record-setting high temperatures that will top 100F in several states.

Heat advisories and excessive heat warnings have been issued across portions of roughly half a dozen states and daily records could be broken in more than 75 cities.

Spiking temperatures will also set the stage for a set of compounding catastrophes across the west, baking moisture out of already parched landscapes. Roughly 44% of the American west is categorized as in extreme drought this week, according to the US Drought Monitor. The punishing weather also increases the risks for wildfire ignitions and contributes to worsening air quality.

In Arizona, Phoenix and Yuma are forecast to be just shy of 115F (46C) on Saturday when the heat peaks across the region. Blythe and El Centro in California will be at or above that temperature. Las Vegas will top out at 111F (44C) during the heatwave, the National Weather Service said.

The dangerous conditions come as summer recreation and outdoor activities begin to ramp up, but officials have cautioned residents and visitors in impacted areas to stay out of the elements. Heeding their calls, the University of California, Davis called off its commencement ceremony on Friday while it was underway. The school has scheduled a separate event for them on Sunday.

An often silent killer that takes more lives than any other kind of extreme weather, rising temperatures pose significant risks to public health that will worsen as the world warms. An investigation by the LA Times published last year found that fatalities from heat are abysmally undercounted in California, and that related deaths could be as much as six times higher than the official tally.

The Associated Press contributed reporting