Fears are growing in France of a substantial death toll from a prolonged heatwave that has caused scorching temperatures on hospital wards and forced the cancellation of several mass events to avoid overwhelming the healthcare system.The heat dome that has caused record-breaking temperatures in continental Europe is expected to move eastward from this weekend. Poland and Germany are braced for temperatures as high as 40 degrees this weekend.Croatia has issued red-level warnings for heat for this weekend, with temperatures of up to 38 degrees forecast for Sunday.Emergency services in France have been inundated with calls for help as successive days of record-breaking heat pushed people to their physical limits, with temperatures as high as 40 degrees during the day and in the mid-20s at night.“Hospitals are beginning to reserve refrigerated lorries in anticipation of mortuaries being unable to cope with the excess mortality,” the major CGT union’s healthworker branch warned in a letter to the prime minister, warning of temperatures on hospital wards as high as 37 degrees.The French ministry of health said that full figures of deaths attributable to the heat were not yet available, but that authorities were “concerned about the occurrence of deaths at home across the country”.[ France’s hottest day: ‘We had 44 degrees. I have a photo of the thermometer’Opens in new window ]Hospitals have been dealing with a surge of heart attacks in the Paris region, and emergency medical responders registered over five times more deaths in a 24-hour period in the capital than normal on Thursday.“I am sure we will see a significant excess mortality,” Samuel Thomas, a doctor with emergency response service SOS Médecins Grand Paris, told a television interview.“The number of death certificates we are asked for ... Personally, in 20 years with SOS Médecins, I have never experienced anything like this.”During the last comparable heatwave in France’s in 2003 there were 15,000 excess deaths, but the toll of the current high temperatures will not be known until full figures are collated in the weeks and months to come.Emergency services in the region of Ille-et-Vilaine in France’s northwest received their highest number of calls in a single day ever on Thursday, exceeding the height of the Covid-19 pandemic, according to its main university hospital in the city of Rennes.[ European heatwave in graphics: Why are temperatures rising faster in Europe?Opens in new window ]The World Meteorological Organisation described heat as a “silent killer”, warning that while the elderly, young children, and people with health conditions were most vulnerable, “heat stress can affect anyone” when extreme heat goes on for days and the body cannot cool down at night.After hospitals in Paris appealed for action to help them cope with a “health crisis” and “extreme pressure” due to the heat, the police prefecture of Paris asked organisers of a music festival, gay pride and an athletics event to call them off of face a ban by decree.The prefecture also banned the consumption of alcohol in public spaces in Paris from midday on Friday and the sale of takeaway alcohol from 6pm due to effects of alcohol “multiplying the risk of heatstroke”.The national government has urged local police authorities across France to consider imposing similar bans.In Ireland, Met Éireann classified the warm spell officially as a heatwave on Friday, but said it was coming to an end, with temperatures set to fall back to between 18 and 23 degrees over the weekend.The transition will see the country become less hot and humid with the return of scattered showers amid sunny spells.Friday saw a high temperature of 28.2 degrees recorded at weather stations in Dublin’s Phoenix Park and in Carlow, lower than the 32 degrees recorded in Athenry, Co Galway, on Thursday.Friday evening was also marked by intense thunderstorms which swept over Clare and Galway throughout the afternoon and further north as the evening went on. Nine counties were under Met Éireann advisories of varying durations and severities on Friday evening.The storms caused serious disruption in places, with thousands of homes, farms and businesses left without power, ESB Networks said.