Southern Europe has been grappling with record-breaking temperatures during the peak summer tourist season, prompting authorities to warn of health risks. Scientists say heatwaves are becoming more frequent, intense and spread out across seasons due to climate change.
In Portugal, more than 900 firefighters and 16 waterbombing aircraft were still battling two wildfires that erupted over the weekend - in Odemira, some 200 km (124 miles) south of Lisbon, and in the town of Ourem, about 140 km north of the capital.
Authorities have declared more than 120 municipalities across Portugal at maximum risk of wildfires.
The factors causing the latest heatwave are a stable atmosphere - leading to cloudless skies - and the arrival of a large mass of hot and dry air from North Africa, Ruben del Campo of Spanish weather agency AEMET, told Reuters.
"This heatwave is going to be generally more intense, more widespread and a little longer-lasting than the two we had in July," he added.
The combination of scorching temperatures and very low humidity caused water in reservoirs to evaporate at a faster rate, just as consumption was also on the rise, worsening the effects of the long-running drought afflicting Spain, he said.
Reservoirs were at 42.2% of their capacity as of July 31, according to Environment Ministry data.
AEMET's Portuguese counterpart IPMA on Monday put six districts in the country - including the capital, Lisbon - on red alert for extreme heat until midnight.
IPMA said temperatures could exceed 44C in Evora, located in the wide plains of the south-central Alentejo region, and 41C in the coastal cities of Lisbon and Setubal.
(Reporting by Miguel Gutierrez in Madrid and Patricia Vicente Rua in Lisbon; Writing by David Latona; Editing by Sharon Singleton)
