July 2019 European heat wave
The July 2019 European heat wave was a period of exceptionally hot weather, setting all-time high temperature records in Belgium, Germany, Luxembourg, the Netherlands, and the United Kingdom. It followed the June 2019 European heat wave, which killed over 567 people, and exceeded previous records by in Belgium, by in Luxembourg, by in Germany and the Netherlands and by in the United Kingdom.
The deaths of 868 people in France and one person in Belgium were reported, along with thousands of animals when ventilation systems in barns were overwhelmed. Due to high river water temperatures and sluggish flows, particularly in France and to some extent Germany, a number of thermal power stations that use once-through cooling and do not have cooling towers had to reduce output or shut down to avoid breaching environmental limits on river water temperature designed to protect aquatic life.
Meteorological history
The heat wave was caused by a strong omega block, consisting of hot, dry air from North Africa, trapped between cold storm systems. The high-pressure area of hot air, called Yvonne, stretched from the central Mediterranean to Scandinavia and was pinned between two low-pressure areas, one over western Russia and the other over the eastern Atlantic.By country
Belgium
On 24 July, the highest ever recorded temperature in Belgium was measured, reaching in the town of Angleur, exceeding the previous record of, reached in 1947. On the same day, passengers were evacuated from a Eurostar train that had broken down between Halle and Tubize, as many began to fall ill due to the extreme temperatures. On 25 July, the record was again broken, reaching in Begijnendijk. One death was reported.Finland
On 28 July, Helsinki recorded a temperature of, breaking the city's previous record. On the same day, was recorded in Porvoo.France
In July 2019, France experienced its second heat wave in less than a month, beating several regional and national temperature records. In the previous month, a national record temperature of was measured in the southern commune of Gallargues-le-Montueux. Nevertheless, more than 50 French cities exceeded their previous high temperature records in this heat wave.On 23 July, 80 departments of France were included in an orange heat wave alert by Météo-France, and 20 departments were included in a red alert the next day. On 24 July, a temperature of was registered by Météo-France in Bordeaux, breaking the city's previous record of in 2003. Similarly, on 25 July, a temperature of was recorded in Paris, also breaking the city's previous record of in July 1947.
On the night of 24–25 July, France saw its hottest night since records began, as the whole country averaged an overnight low of, exceeding the record from the 2003 heat wave. Bordeaux saw an overnight low of, beating the previous record of 25 °C ; Lille saw, exceeding the July 2007 record of. Lille also saw a high of the following day, above the record of that had been set the previous year.
Also on 25 July, the chief architect of the Notre-Dame de Paris cathedral told media that he feared that the heat wave could cause the cathedral's vaulted ceilings, damaged in an April 2019 fire, to collapse. While he indicated the stone walls were still stable for the time being, he explained that the walls were still saturated with water sprayed by firefighters during the blaze, and rapid drying from the extreme temperatures could adversely affect the stability of the structure.
Two nuclear reactors in southwest France were shut down and the output of six reactors were curtailed to avoid breaching environmental limits on the temperature of the rivers they use for cooling water. This reduced French nuclear power generation by around 5.2 gigawatts at a time of increased electricity demand due to the use of cooling devices.
According to the French Ministry of Health, 868 people were reported to have died in France as a result of the heat wave.
Germany
On 25 July, a temperature of was recorded in Lingen, Lower Saxony. This beat the record for the highest ever temperature recorded in Germany, following its previous record of measured a day earlier. Twenty-five weather stations in the country reported temperatures of or higher on 25 July. Prior to this heat wave, the highest recorded temperature in Germany was in Kitzingen in 2015.At the end of the heat wave, on the evening of 26 July, a maximum purple alert for storms was issued for three districts of the Land Baden-Württemberg, namely Freudenstadt, Böblingen and Calw.
Greenland
After the heat wave ended in mainland Europe, the mass of warm air traveled north to Greenland, causing a heat wave that led to a melting of some of ice in July. The melting was forecast to peak on 1 August. For comparison, the entire melt season in 2012 caused gigatonnes of ice loss. A record 56.5 percent of Greenland Ice Sheet was showing signs of melting on 31 July. US National Snow and Ice Data Center estimated ice loss during the first week of August at per day with a total loss of for the melt season to date.A wild fire which has been burning near Sisimiut since early July necessitated dispatching firefighters from Denmark, as the fire was endangering inhabited areas and had the potential to continue burning through the winter. Forest fires are exceedingly rare in Greenland.
Luxembourg
On 25 July, a red alert for extreme heat was put in place for the entire country by Meteolux. The same day, a temperature of was measured in Steinsel, the highest ever recorded in the country, beating the record of set in Remich in 2003.The high heat and dry conditions caused several fires during the heat wave. On 24 July, a fire broke out near Schumannseck, and hay bales caught fire in a field. On 25 July, a bush fire occurred in Hamm, and a fire truck exploded when it became engulfed in flames whilst attending the scene.
Netherlands
In the Netherlands, an orange alert was put in place for the entire country due to the extreme heat. The previous high temperature heat record, set in Warnsveld in 1944, was broken on 24 July in Eindhoven where the temperature reached. The following day, was measured in Gilze-Rijen. The West Frisian Islands was the only region for which no weather alert had been issued but there was a heatwave for the first time ever on Vlieland and Terschelling since measurements started in 1996.On 27 July, the KNMI ended the orange alert for South Holland, Zeeland, North Brabant and Limburg. The same day at 22:32 CEST they ended the orange alert for the whole country.
On 22 July, ProRail announced code red for traffic controllers, as extra alertness was necessary for disturbances on the tracks and other problems due to heat. On 25 July, NS cancelled services on the Schiphol–Antwerp high-speed railway between Amsterdam—Schiphol—Rotterdam, and the connection between Amsterdam—Eindhoven and Eindhoven—Heerlen. As trains were exposed to high temperatures, more maintenance was required and some were taken out of service. Units without air conditioning or openable windows were also taken out of service. This continued into the following day, except with four other routes made unavailable; Amsterdam—Alkmaar, Amsterdam—The Hague, Duivendrecht—Lelystad and Schiphol—Nijmegen.
Many farm animals died as a result of the high temperatures, mainly due to ventilation systems failing. Due to a power failure in a chicken barn in Neer, 4,000 chickens died. Hundreds of chickens also died whilst being transported to Poland on 24 July because of rising temperatures. On the same day, hundreds of pigs died in Middelharnis because of power failure in ventilation systems, and 2,100 pigs died in Maarheeze as barns reached temperatures of.
Nearly 400 extra people were reported to have died during the heatwave compared to a regular summer week.
Norway
On 26 July, a temperature of was recorded in Bergen in Norway, setting a new temperature record for the city. A day later, at Laksfors railway station south of Mosjøen, a temperature of was recorded, equalling the national all-time temperature record first set in June 1970. However, the Norwegian Meteorological Institute later did not approve the recording due to too much gravel and too high vegetation near the station. The highest recording approved was at the Mosjøen Airport on 27 July, the warmest temperature ever recorded in Northern Norway and a tie with the all-time national high for July. The same day, a temperature of was recorded further north in Saltdal; this is highest temperature ever recorded inside the Arctic Circle in Norway. Also on 27 July, Trondheim Airport recorded a new all-time high with and saw five consecutive days with high above.At Sømna-Kvaløyfjellet, a weather station on a coastal hill ASL in Nordland in Northern Norway, the overnight low on 28 July did not go below, beating the previous national record for the warmest night of recorded 6 degrees of latitude further south in Halden, south of Oslo, in July 1933.
The Norwegian Meteorological Institute said that it had recorded "tropical nights" in 20 locations in the south of the country, where temperatures stayed above throughout the night.
Sweden
On 26 July, a temperature of was recorded in :sv:Markusvinsa|Markusvinsa, the highest temperature recorded in the north of Sweden since 1945. The Swedish Meteorological and Hydrological Institute issued a Class 1 heat warning for parts of the country, as well as a warning for potential water shortages in August in 15 counties. To prevent forest fires due to the heat and dry weather, fire bans were also put in place in several locations in Sweden. However, a meteorologist at the institute stated that although above average, temperatures in the south of the country were not as extreme. Mainly, the reason for this was that July started with a cool spell in Northern Europe in between the two heat waves.United Kingdom
On 23 July, Public Health England renewed a heat warning for the whole of the United Kingdom, urging people to "keep hydrated, find shade and take protection against the sun". On the same night, widespread thunderstorms affected the country, with BBC Weather reporting around 48,000 lightning strikes overnight.On 25 July, the Met Office announced that the United Kingdom had its hottest July day on record, with a temperature of recorded at the National Institute of Agricultural Botany in Cambridge. This beat the previous July record of in 2015, and marked the second time in history that the country had recorded a temperature higher than. On 29 July, the Met Office announced confirmation that sensors at the Cambridge University Botanic Garden recorded a temperature of on 25 July, breaking the national all-time record of set in Brogdale, Kent, on 10 August 2003.
New local temperature records were set in towns and cities across the country on 25 July, including in Edinburgh and in Sheffield.
Impact on British transport and flights
On 25 July, Network Rail began to impose speed restrictions across its network to reduce buckling rails, as track temperatures surpassed. Measures also included painting railway tracks white to reduce the temperature of the steel, and cancelling services. East Midlands Trains, Southeastern and Greater Anglia advised passengers against all but essential travel.Many heat-related incidents on the country's rail network caused widespread disruptions, especially affecting intercity services from London. Damage to overhead line equipment occurred in Peterborough, Handsworth and Camden, as well as a trackside grass fire caused by cables snapping near West Hampstead. Trains arriving and departing from Birmingham New Street and around the West Midlands were also disrupted. Passengers were advised not to start new journeys as the overheating of overhead cables rendered many services unable to run.
On 26 July, all but essential travel had been advised against, after the extreme heat and storms caused severe disruption to the rail network and airports. Thameslink ran reduced services, with half of its lines unavailable. East Midlands Trains services between Sheffield, Nottingham, Derby and London St Pancras were disrupted due to overhead wire damage from the heat of the previous day, and an emergency timetable was put in place. All Eurostar services to and from Paris were also suspended for an "undetermined amount of time" due to an exploded cable, as well as delays lasting up to an hour on Brussels services.
Several flights were cancelled and delayed from Heathrow, Gatwick and London City airports due to "extreme weather conditions across Europe". A spokesperson from Heathrow said that flights had been affected by overnight storms as a result of the heat.
Research
As of 1 August, the World Meteorological Organisation considered July 2019 to be at least tied for the hottest month ever recorded, based on global average temperature. Previously, June 2019 was found to be the hottest June on record. This was confirmed on 5 August by EU Earth Observation Network, which found it hotter than the previous record-holder, July 2016. 2019 on the whole was found to be on track for the new hottest year on record.A study of the event, a collaboration between several European climatological organisations and institutes, was published on 2 August 2019. It found that the temperatures experienced during the heat wave would have been lower had it not been for anthropogenic global warming, and that temperatures recorded in France and Netherlands would have occurred there on average less than once a millennium. According to the study's lead author, at the current pace of warming, such heatwaves will be another stronger by 2050.