French heatwave kills 18: What is Omega Block that's charging Europe's deadly weather?

A powerful heatwave is sweeping across Europe, pushing temperatures above 40°C in several countries. Here's what's causing the extreme heat and which nations are worst affected.

In Short

• UK may break June heat record, second-ever heat-health alert issued
• France reports at least 18 heat-related deaths and record temperatures
• Heatwave caused by a weather system drawing hot air from North Africa

A fatal heatwave has gripped much of Europe, pushing temperatures above 40°C in several countries, triggering health alerts, disrupting transport services and contributing to multiple deaths.

At least 18 people died in France, including two children left in a hot car, according to news agency Reuters. Meanwhile, the temperature in Bordeaux in France's western wine country rose to 41.9°C, breaking a record set last August.

An April report by the World Meteorological Organisation (WMO) found Europe is warming at more than double the global rate.

THE HARDEST HIT EUROPEAN NATIONS

The United Kingdom (UK) could see temperatures reach 39°C this week, potentially breaking its all-time June temperature record of 35.6°C, set in 1957 and matched in 1976.

The UK Met Office, the nation's weather authority, has issued its second-ever nationwide heat-health alert, warning that the extreme temperatures could pose risks even to healthy people.

The agency has also issued a red alert for Wednesday and Thursday across six regions in England. While the nation is prepping for extreme heat, London is presently witnessing a thunderstorm, showing acute weather variability in the region.

Apart from the UK, France has also emerged as one of the worst-affected countries.

Temperatures have exceeded 42°C in some areas, while Bordeaux recorded 41.9°C, setting a new local temperature record. Authorities have expanded heatwave alerts across large parts of the country and held emergency meetings as the scorching conditions continue.

The heatwave has already been linked to at least 18 deaths in France, including elderly residents and two children who were left in a parked vehicle, according to news agency Reuters. Officials have also reported a rise in drownings as people seek relief from the heat in rivers, lakes and other unsupervised water bodies.

Weather forecasters in France warned that the soaring temperatures could match the 2003 heatwave that killed 15,000 people in the country.

Spain is also enduring its first official heatwave of 2026, with temperatures reaching 39-40°C across parts of the country.

Authorities have warned of increased wildfire risks and urged residents and tourists to avoid prolonged exposure to the sun.

Meanwhile, Italy on Monday issued heatwave red alerts for 12 cities as temperatures continue to climb.

WHAT CAUSED THE HEATWAVE?

Meteorologists say the heatwave is being driven by a persistent high-pressure system, sometimes referred to as Omega Block, which is creating a heat dome over Europe, drawing hot air northward from North Africa and trapping it over western and central Europe.

Omega Block and heat dome are related to each other but not the same.

In simpler words, the Omega Block is the cause and the heat dome is the consequence.

Omega Block is a stagnant atmospheric pattern where a high-pressure system is sandwiched between two low-pressure systems, locking extreme weather in place for days.

That locked extreme weather is what a heat dome is; a weather phenomenon where a large area of high pressure in the upper atmosphere becomes stationary over a region, trapping hot air beneath it, much like a lid on a pot.

The formation of the heat dome follows an unusually hot May across Europe.

According to the European Union's (EU) Copernicus Climate Change Service (C3S), western Europe experienced one of its most intense early-season heatwaves on record, with several countries breaking May temperature records.

For those in India, the scale of the event is notable because temperatures above 40°C are relatively common in parts of India during summer but remain unusual for many European countries, where homes, transport systems and public infrastructure are generally less adapted to prolonged extreme heat.

As a result, even temperatures that might seem routine in parts of India can have significant impacts across Europe.

- Ends