People sunbathe on a beach during a hot summer day in Barcelona, Spain, Saturday, Aug. 4, 2018. Hot air from Africa is bringing a heat wave to Europe, prompting health warnings about Sahara Desert dust and exceptionally high temperatures that could peak at 47 degrees Celsius (117 Fahrenheit) in Spain and Portugal. (AP Photo/Manu Fernandez)

Villagers take refuge at a shelter in Paksong town, Champasak province, Laos on Wednesday, Jul. 25, 2018. Rescuers were searching Wednesday for villagers left missing when part of a newly built dam broke in southeastern Laos, flooding the surrounding countryside and killing at least 19 people. (AP Photo/Hau Dinh)

A villager takes refuge on a rooftop above flood waters from a collapsed dam in the Attapeu district of southeastern Laos, Tuesday, July 24, 2018. The official Lao news agency KPL reported Tuesday that the Xepian-Xe Nam Noy hydropower dam in Attapeu province collapsed Monday evening, releasing large amounts of water that swept away houses and made more than 6,600 people homeless. (Attapeu Today via AP)

Villagers take refuge on a rooftop above flood waters from a collapsed dam in the Attapeu district of southeastern Laos, Tuesday, July 24, 2018. The official Lao news agency KPL reported Tuesday that the Xepian-Xe Nam Noy hydropower dam in Attapeu province collapsed Monday evening, releasing large amounts of water that swept away houses and made more than 6,600 people homeless. (Attapeu Today via AP)

A park ranger patrols an area Friday, July 20, 2018, near where a duck boat capsized the night before resulting in at least 13 deaths on Table Rock Lake in Branson, Mo. Workers were still searching for four people on the boat that were unaccounted for. (AP Photo/Charlie Riedel)

FILE - In this Nov. 8, 2012 file photo, TVA contract workers remove coal ash from the edge of the Emory River next to the Kingston Fossil Plant in Kingston, Tenn. as part of the cleanup from a December 2008 spill. The Trump administration is easing rules for handling toxic coal ash from more than 400 coal-fired power plants across the U.S. after utilities objected to regulations adopted under former President Barack Obama. Environmental Protection Agency acting Administrator Andrew Wheeler said Wednesday, July 18, 2018, the changes will save utilities roughly $30 million annually. (Michael Patrick/Knoxville News Sentinel via AP, File)

In this undated photo provided on Tuesday, July 17, 2018, by the North Korean government, North Korean leader Kim Jong Un, center, speaks during a visit to a machine factory in North Hamgyong Province, North Korea. State media say that Kim has harshly reprimanded local officials over a delayed construction project. Independent journalists were not given access to cover the event depicted in this image distributed by the North Korean government. The content of this image is as provided and cannot be independently verified. Korean language watermark on image as provided by source reads: "KCNA" which is the abbreviation for Korean Central News Agency. (Korean Central News Agency/Korea News Service via AP)