‘Wet bulb’ warning as ‘dangerous and record-breaking heat’ to hit millions in US this week

In some places, temperature and humidity will combine to form potentially hazardous ‘wet-bulb’ conditions

Over 30 million people are under heat advisories or warnings as extremely high temperatures continue their spread over the southern and central US this week.

The National Weather Service says that heat this week will be “well-above normal”, with the potential to break local records. Temperatures around 110 degrees Fahrenheit (43 degrees Celsius) are possible near Dallas, Texas on Monday — with highs above 100F (38C) stretching all the way north into Montana.

That heat will linger through the week across the southern Plains.

This heatwave in the US comes as much of Europe is experiencing devastating and record-breaking heat — and the planet is facing a climate crisis that makes extreme heat more and more likely.

Texas, Oklahoma and Kansas will be hit especially hard this week, with high temperatures regularly well above 100F (38C). Parts of the northern Texas panhandle are currently under an “excessive heat watch” with temperatures hitting up to 115F (46C).

Aerial view of the Coachella Canal running past agricultural fields next to undeveloped desert near Mecca, California. More than 97 per cent of California's land area is in at least severe drought status, with nearly 60 per cent in at least extreme drought (Getty Images)

But combined with humidity, heat in many parts of the country are supposed to reach potentially hazardous conditions. On Monday, much of the Dakotas and Minnesota will experience “extreme” wet bulb globe temperatures — a measure of the human body’s ability to cool itself off.

During high wet bulb temperatures, temperature and humidity combine to make conditions especially dangerous for those exposed for a long time. People like outdoor workers and athletes who practise outside should take special caution.

Extreme wet bulb temperatures will continue through the south and even across the Atlantic seaboard by the rest of the week.

The country may not get much of a respite from these temperatures anytime soon, either. According to the National Oceanic and Atmospheric Administration (NOAA), the vast majority of the country should expect to see above average temperatures starting this weekend and continuing over the following week.

NWS encourages people to stay hydrated, limit outdoor activities and check up on other people — especially the most vulnerable, like the elderly — to protect yourself and other from the dangers of extreme heat.

High temperatures and humidity can lead to life-threatening illness and risks, including heat stroke and death.

And this heat wave is just the latest in what is turning out to be a hot summer for parts of the country. Last month, San Antonio, Texas recorded 17 days with high temperatures above 100F (38) — while the norm for June is just two days, reports The New York Times.

This kind of heat is expected to become even more common as the climate crisis grows over the next few decades.

As the world reaches 2C of warming above 19^th century temperatures, heatwaves that once happened every 10 years would occur about every other year, according to the most recent report from the Intergovernmental Panel on Climate Change (IPCC).

Currently, the world has warmed around 1.2C.

But the climate crisis may not just lead to more of the intense and rare events — it may also raise temperatures on more normal summer days. According to the Climate Shift Index, a measure of how much the climate has affected each day’s temperature in the United States, many of the highs expected across the central and southern Plains this week have become more likely due to the climate crisis.

In northern Texas on Tuesday, where temperatures will reach up to 115F (46C), the climate crisis has made those conditions at least five times more likely to occur than before, the index says.

In Europe, a massive heatwave has broken records and lead to wildfire outbursts in the UK, France, Spain and Portugal. On Monday, Wales broke its all-time record temperature — and the UK’s all-time record temperature is expected to be broken as well.