London Faces Second Heatwave Alert as Temperatures Soar

London was issued a health alert because of heat wave conditions for a second day as Britain basked in its hottest spell since 2006.

The U.K. Met Office posted the alert on its website, indicating there’s a 90 percent chance of temperatures in the capital hitting 32 degrees Celsius (89.6 degrees Fahrenheit) today and tomorrow. Hampton Water Works in southwest London had the U.K.’s hottest day of the year yesterday, at 32.2 degrees.

The warm spell began on July 6, and today will be the 13th day in a row where temperatures somewhere in the U.K. exceed 28 degrees, according to the Met Office. That’s the longest stretch since a 16-day period in 2006. The heat is driving up water demand, threatening the country’s wheat crop and may pose a danger to human health. The fire brigade has reported an uptick in grass fires, including one in south London today.

“Heat waves can be dangerous especially for very young people and the very old,” Sarah Holland, a spokeswoman for the Met Office, said by phone.

The heat wave to date may have killed as many as 760 people, the Times newspaper reported today, citing research it commissioned from the London School of Hygiene and Tropical Medicine. A spokeswoman from the school said today by phone that the central calculation is of 650 heat-related deaths.

London Blaze

“As temperatures rise above a certain threshold, the risk of death increases,” Ben Armstrong, a statistician at the school, said in an e-mailed statement. “We estimate that the current heatwave has caused the premature deaths of 650 people. The excess is likely to have been overwhelmingly among the elderly, especially those over 75, some of which may have been among people who would have died just a few weeks later if there had been no heatwave.”

Two army reserve soldiers died while training in the heat in Wales at the weekend, the Ministry of Defence said July 15.

Four hectares of Mitcham Common, equivalent to the size of four soccer fields, were ablaze today, according to Martin Simpson, a spokesman for the London Fire Brigade. About 15 firefighters are tackling the blaze, which was reported at noon, he said.

Grass fires have surged to 21 a day this July from five a day in the first half of July 2012, according to the brigade. Incidences since May 1 are almost double last year’s total.

Cigarette Sparks

“A small spark from a cigarette is often all it takes to start a grass fire in these dry conditions,” Dave Brown, head of operations at the brigade said in an e-mailed statement. Drivers “need to take care not to throw cigarettes out of car windows as they can easily burn grass verges.”

The brigade warned civilians not to attempt to extinguish fires themselves. They also advised Londoners to take preventative measures such as not leaving camp fires or barbecues unattended and clearing away bottles and broken glass that could otherwise magnify the sun’s rays.

Heat wave health watches are also in place in southeast England, southwest England and the west Midlands, according to the Met Office website. The threshold for a heat wave varies by region. It’s 31 degrees in the southeast and 30 degrees in the other two areas.

“Experience tells us that exposure to excessive heat can kill, with most cases of illness and death caused by heart and lung disease,” Doctor Paul Cosford, director for health protection at Public Health England, said yesterday in a statement. “Because we are not used to these very hot temperatures in England, it’s important that local plans are in place to reduce the impact of harm from very hot weather.”

Water Demand

In southern England, Kemble Water Holdings Ltd.’s Thames Water unit, the country’s biggest supplier, said demand for tap water by its 9 million customers has risen by 15 percent across London, enough to fill 160 Olympic-sized swimming pools a day.

Affinity Water Ltd. said peak demand has increased by as much as 27 percent and asked customers to use water “wisely.” Affinity, which serves 3.5 million people in southern England, is owned by Morgan Stanley Infrastructure Partners and Prudential Plc’s M&G investment arm.

After a cold and wet spring slowed crop development earlier this year, the summer heat and dry conditions may damage wheat that’s not had the chance to lay roots as deep as usual, Charlotte Garbutt, a senior analyst at the Agriculture & Horticulture Development Board said yesterday.

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