Europe is sweltering under a heat dome pushing temperatures in parts of the continent to 46C, as deaths rise and the risk of disaster grows.The ⁠spike in temperatures is being driven by a mass of hot air moving north from the Sahara, fuelled by a strong high‑pressure ​system known as the 'African anticyclone.'Meteorologists say the system is creating a so‑called 'heat dome,' trapping hot air over western and central Europe and ​allowing temperatures to build day after day.In France, 20 people have tragically drowned since the beginning of the weekend, while seeking reprieve from the heat.The government's emergency response cell warned people not to try to cool off in unsupervised areas such as lakes and rivers, after the drowning deaths at the weekend, which included a 13-year-old girl, according to the civil defence authorities. Similarly in Germany, a spike in fatal swimming accidents saw five deaths over the weekend.Two men aged 20 and 22 drowned in lakes in Bavaria, and a 79-year-old woman died in the Baltic Sea. Other fatal swimming accidents occurred in lakes in Brandenburg and North Rhine-Westphalia.It comes as two children were found dead in a car in France. The toddlers, aged two and four, were found unconscious by their mother in the family car outside their home in Carpentras. The ⁠spike in temperatures is being driven by a mass of hot air moving north from the Sahara The French government's emergency response cell warned people not to try to cool off in unsupervised areas such as lakes and rivers Tourists visit Piazza dei Miracoli near the Leaning Tower of Pisa during a heatwave Tourists and Parisians cool off at Eiffel Tower, amid a heatwave in Paris The Golfech plant near Toulouse is cooled by the Garonne river but the water had warmed beyond the safe level of 28 CelsiusAnd France has switched off a reactor at a nuclear plant near Toulouse because cooling water drawn from a nearby river had gotten too warm, a spokeswoman said.The Golfech plant near Toulouse is cooled by the Garonne river but the water had warmed beyond the safe level of 28 Celsius.Harsh temperatures are expected to linger until at least Thursday, with conditions possibly intensifying as the week continues. The European heat dome comes after a May that saw several countries report record temperatures for that time of year.Weather bosses have put 49 of the 96 mainland departments on a red alert weather warning, up from 35 over the weekend.Paris officials have warned people to avoid travel. 'The transport network comes under severe strain in periods of extreme heat... railways cannot withstand temperatures above 50 degrees,' the head of the Ile-de-France greater Paris region, Valerie Pecresse, told journalists.'That is why we have advised all passengers who can to postpone their journeys, particularly vulnerable people, and for everyone who is able to work from home to do so.'Forecasters warned that scorching weather could end up being as serious as a 2003 heatwave that claimed the lives of nearly 15,000 people nationwide.Over in Spain, where parts of the centre and northeast hit 40C, authorities issued a swathe of orange and red weather warnings across large parts of the Iberian Peninsula and Mallorca.Spanish weather bosses said the country's heatwave would last until at least the middle of the week.Over the weekend, Madrid authorities cancelled a public screening of Spain's World Cup match against Saudi Arabia on Sunday amid health fears.The Spanish football federation (RFEF) said the screening at Plaza de Colon, where supporters could watch Spain's World Cup ​matches on large screens, has been called off.In Barcelona, people were seen diving into outdoor pools to cool off over the weekend.And over in Seville, the mercury hit 40C on Sunday afternoon, while the previous day saw temperatures in Mallorca hit a staggering 42C.In Germany, where temperatures ​have already reached as high as ​38C, the DWD weather service ⁠warned of severe thunderstorms in eastern regions including Berlin, where heavy rain disrupted the open‑air Fête de la Musique festival.Organisers had to evacuate the grounds of the Berlin Open as heavy rain and strong ​winds set in, and as fans awaited the tennis tournament's singles final between Jessica Pegula of ​the US and ⁠Linda Noskova of the Czech Republic.And in Italy, 15 cities are now on red alert, with the number expected to rise to 16 cities on Wednesday.The cities are Bologna, Bolzano, Brescia, Florence, Frosinone, Milan, Perugia, Pescara, Rieti, Rome, Turin, Verona, Venice, Viterbo, and Ancona.Latina in Central Italy will join the list on Wednesday. In Rome, people were seen cooling off in water fountains in the city's Piazza Venezia. A tourist cools off at a fountain in Cordoba, Spain A couple eat an ice cream to cool off in Bilbao, Spain, as the temperature behind them reads 37C A woman waves a fan during a heatwave in Milan, Italy People shield themselves with umbrellas from the sun during Thom Browne's Spring/Summer 2027 men's collection show as part of Milan Fashion Week People cool off in ornamental fountains as high temperatures affect Berlin, GermanyMeanwhile, temperatures in Belgium are expected to be 'the hottest ever recorded' there in the coming week, warned David Dehenauw, head of forecasting at the IRM meteorological institute.Belgium's national rail company SNCB announced that some rush hour trains had been cancelled for Monday and Tuesday to reduce the risk of breakdowns blocking the tracks amid the heat dome.And over the weekend, Greece saw a wildfire break out on the island of Syros.Four firefighting aircraft were sent to battle the blaze. Authorities issued an evacuation notice for nearby villages.It is not currently clear how the fire broke out, though it was brought to heel on Sunday.Another wildfire in Greece, this one in the northern town of Maroneia, was also quashed.Here in the UK, Liz Bentley, chief executive of the Royal Meteorological Society, predicted that existing UK heat records for June would be 'annihilated' - as had already happened in May.'The coming week will bring an unprecedented heatwave with temperatures likely to reach 38-39 degrees Celsius,' she predicted. 'The current June record is 35.6 degrees Celsius.'This will lead to two consecutive months, May and June, in which the UK temperature records have been annihilated by well over 2C,' she added.The UK's meteorological office issued the highest level of heat warning for parts of central and southern England for Wednesday and Thursday, with temperatures in the shade potentially rising as high as 40C in some places.'An exceptional spell of hot and humid weather is expected across this region' covering London, Birmingham, Bath and other areas of England, the Met Office said Monday, a month after Britain broke its May temperature record.'It is now likely the current highest temperature on record for June will be broken, this being 35.6C recorded in Southampton in June 1976 and Camden Square in June 1957,' the forecaster said.The UN has warned that the weather over the next five years will likely see more shattered heat records.Akshay Deoras, a senior researcher at the University of Reading's National Centre for Atmospheric Science, in England, said it was clear what was behind the rash of heat records.'Human-driven climate change has provided the springboard for this event, loading the atmosphere with extra heat and making extreme temperatures far more intense than they would have been in the past,' he said.A study found that human-caused climate change led to the deaths of 1,500 people across Europe during an unusual May heatwave.