Emergency services work at the scene of a bus accident on the Kingsway in central London February 2, 2015. A number 91 double-decker bus had its roof ripped off after hitting a tree, causing injury to passengers and passers-by, local media reported. (Photo by Peter Nicholls/Reuters)

An unmanned Antares rocket is seen exploding seconds after lift off from a commercial launch pad in this still image from video shot by Matthew Travis of Zero-G News from the press area at Wallops Island, Virginia October 28, 2014. The 14-story rocket, built and launched by Orbital Sciences Corp, bolted off its seaside launch pad at the Wallops Flight Facility at 6:22 p.m. EDT/22:22 GMT. It burst into flames moments later, then plunged to the ground in a huge ball of fire and smoke, but authorities said no one was hurt. The cause of the accident was not immediately known. (Photo by Matthew Travis/Reuters/Zero-G News)

Afghan police officers secure a transportation headquarters that was besieged for two days last weekend, on May 14, 2011 in Kandahar, Afghanistan. Taliban gunmen and suicide bombers unleashed a major assault May 7, 2011 on locations in Kandahar that included the governor's compound, the mayor's office, police stations, and an intelligence agency headquarters. (Photo by Majid Saeedi/Getty Images)

People walk past a downed tree in Central Park on October 31, 2011 in New York City. Central Park may lose 1,000 trees following a freak October snowstorm while the park only lost 125 trees due to Hurricane Irene. (Photo by Mario Tama/Getty Images)

A Royal Air Force search and rescue helicopter prepares to leaves RAF Valley as the search continues for the crew of cargo vessel The Swanland which sank off north Wales on November 27, 2011 in Anglesey, Wales. (Photo by Christopher Furlong/Getty Images)

Jeremy Davis (L) demonstrates the operation of the safe room shelter door lock to homeowner Rob Hamlin on June 18, 2011 in Neosho, Missouri. Once thought of as a luxury item there has been a surge of interest from homeowners in purchasing shelters to ride out damaging storms ever since a F5 tornado tore through the town of Joplin, Missouri. Ranging in price from $3,000 to $5,000 homeowners can supplement the cost with a mortgage insurance program offered by the U.S. Department of Housing and Urban Development for installing a safe room built to FEMA specifications. Lawmakers in Alabama have even considered requiring construction of storm shelters in mobile home parks after forty people died in April. (Photo by Julie Denesha/Getty Images)

Actress Nora Arnezeder arrives at NBC Universal's 69th Annual Golden Globe Awards After Party at The Beverly Hilton hotel on January 15, 2012 in Beverly Hills, California. (Photo by Frederick M. Brown/Getty Images)

People brave the wind on the waterfront of Victoria Habour as Typhoon Haima approaches Hong Kong, Friday, October 21, 2016. Typhoon Haima churned toward southern China on Friday after smashing into the northern Philippines with ferocious wind and rain, triggering flooding, landslides and power outages. (Photo by Vincent Yu/AP Photo)