Flights cancelled in South-west American heatwave, but you can bake biscuits on your dashboard

In Arizona zookeepers fed tigers frozen fish while meteorologists baked biscuits in their van

An airliner is distorted by the heat waves rising up from the north runway at Sky Harbor International Airport in Phoenix (AP)

It’s commonly held here in Los Angeles that the Valley is always several degrees warmer than the Hills, which are always several degrees warmer than the beach. That goes some way to explaining why the pavements of San Fernando were all but empty, and the beaches brimming from Malibu to Marina del Rey on Sunday morning in the midst of a searing heatwave that spans the entire US South-west.

A handful of LA neighbourhoods recorded temperatures in excess of 38C (100F) on Saturday afternoon, and a number of residents were treated for heat stroke and dehydration. That was as nothing to the rest of the region, however: in Palm Springs, a desert town some 100 miles east of LA, temperatures climbed as high as 50C.

In Las Vegas, one man was found dead by paramedics in a non-air-conditioned home on Saturday; his existing ailments were thought to have been exacerbated by the extreme heat. Another elderly man was hospitalised with heat stroke after the air conditioning in his car gave out on a desert road trip. The Running With the Devil Marathon, due to be held on Saturday outside the city in the Mojave Desert, was cancelled, while around 200 people attending an outdoor concert in Las Vegas required medical treatment – more than 30 of them were taken to hospital.

As officials warned that the blistering temperatures could rise further and would last well into the week, air-conditioned “cooling centres” were set up in a number of Western states. The heatwave comes only a fortnight before the centenary of the highest temperature ever recorded, 56.7C , in California’s Death Valley on 10 July 1913. On Saturday the US National Weather Service said the mercury in Death Valley hit 51.7C.

In Phoenix, Arizona, which experienced a mid-afternoon high of 48.3C on Saturday, US Airways cancelled 18 flights; its planes are allowed to take off only in temperatures of up to 47.8C. The city’s homeless shelters added extra beds, while its zookeepers hosed down their elephants and fed their tigers frozen fish.

Meteorologists with the National Weather Service in Arizona took the opportunity to bake a tray of biscuits – on the dashboard of their van.

At the US border with Mexico, patrol units beefed up their rescue operations, warning that the extreme heat could endanger anyone trying to cross into the US illegally on foot. The Arizona desert has claimed the lives of at least seven such migrants in the past week, all of whom were found dead due to suspected dehydration or heat exhaustion.

Meteorologists say the heatwave is being caused by a high-pressure weather system sitting over the region, trapping the hot air beneath it. It follows one of the South-west’s driest recorded winters, and firefighters feared the heat could spark deadly bush fires.

National parkland in Ventura county, just west of the San Fernando Valley, has only just reopened in the wake of May’s Springs fire, which burnt more than 24,000 acres along the southern California coastline. The California Department of Forestry and Fire Protection says it has responded to around 2,900 fires already since January.