A ballet dancer practices in the sunshine at the Southbank skatepark in London on Monday, September 17, 2018, as Storm Helene is due to bring unseasonably warm weather in London and the south east, as the low pressure draws up warm air from the south. Forecasters have downgraded warnings that Helene could pose a risk to life when it hits this week – but warned coastal communities to stay vigilant. (Photo by Kirsty O'Connor/PA Wire)

Frost covers part of the face of University of Minnesota student Daniel Dylla during a morning jog along Mississippi River Parkway Tuesday, January 29, 2019, in Minneapolis. Extreme cold and record-breaking temperatures are crawling into parts of the Midwest after a powerful snowstorm pounded the region, and forecasters warn that the frigid weather could be life-threatening. (Photo by David Joles/Star Tribune via AP Photo)

A Zimbabwean subsistence farmer holds a stunted maize cob in his field outside Harare, January 20, 2016. About 14 million people face hunger in Southern Africa because of a drought that has been exacerbated by an El Nino weather pattern, the United Nations World Food Programme (WFP) said on Monday. In Zimbabwe, 1.5 million people, more than 10 percent of the population, face hunger, WFP said. (Photo by Philimon Bulawayo/Reuters)

U.S. Army soldiers carry an injured soldier who was shot in the leg, through a poppy field on April 24, 2011 in the Arghandab River Valley, Kandahar Province, Afghanistan. The injured was evacuated to a waiting Blackhawk UH-60A helicopter by Task Force Thunder Brigade, Charlie company 1st of the 52nd Aviation regiment from Fairbanks, Alaska. It is feared that as weather improves with the approaching summer that the casualty toll will rise. (Photo by Paula Bronstein/Getty Images)

Hardy Dutch swimmers brave the icy North Sea on January 1, 2012 in Scheveningen, Netherlands. A record number of 10,000 people took the plunge in this year's traditional New Year's dip. The high turnout was attributed to the mild weather with a sea temperature of 8 degrees compared to 4 degrees last year. (Photo by Jasper Juinen/Getty Images)

A kite surfer takes advantage of high winds and waves off Blackpool seafront on January 12, 2012 in Blackpool, England. Meteorologists are predicting calmer weather after high winds hit many parts of the North West today. (Photo by Christopher Furlong/Getty Images)

Girls look at a newly installed “Renew” media point in the City of London on January 26, 2012 in London, England. The “pods” will transmit each market day and will include breaking news, weather and travel information, and information about sport, fashion, the arts and entertainment. The stations which will also double as recycling points are run by media company Renew. (Photo by Dan Kitwood/Getty Images)

A rescue helicopter is shown at the Mount Everest south base camp in Nepal a day after a huge earthquake-caused avalanche killed at least 17 people, in this photo courtesy of 6summitschallenge.com taken on April 26, 2015 and released on April 27, 2015. Rescue teams, helped by clear weather, used helicopters to airlift scores of people stranded at higher altitudes, two at a time. (Photo by Reuters/6summitschallenge.com)