A solidified mudflow covers State Highway 504 near the town of Toutle, northwest of Mount St. Helens, to a depth of 2 m (6 ft). Geologist for scale. USGSA wrecked logging truck and crawler tractor are shown amidst ash and downed trees near Mount St. Helens two days after an explosive eruption. The AtlanticFifteen-year-old Heidi Havens gives Allen Troup, 16, a kiss as he prepares to board a Spokane City bus, on May 27, 1980. Spokane residents had to wear face masks while outside for days after the eruption because of possible health threats from volcanic ash sprayed over the area by Mount St. Helens on May 18. Ralph Viggers/ APAerial view of timber blowdown, destroyed by the May 18 eruption of Mount St. Helens, in Skamania County, Washington, on June 8, 1980. The AtlanticAn aerial view of the destruction of logging operation after floods following Mount St. Helens’ eruption, shown on May 20, 1980. Jack Smith/ APBlowdown of trees from the May 18, 1980, eruption of Mount St. Helens, viewed on August 22, 1980. Lyn Topinka/ USGADamaged equipment on the south side of Elk Rock, northwest of Mount St. Helens, in Cowlitz County, Washington, on June 5, 1980. USGADenuded trees lay like matchsticks in the changed landscape around Mount St. Helens, shown two days after the eruption, on May 20, 1980. Jack Smith/ APMount St. Helens, shortly after the eruption of May 18, 1980. The AtlanticSteam rises from hot water in a river following the aftermath of the eruption of Mount St. Helens, on May 19, 1980. The AtlanticThe crater left at the summit of Mt. St. Helens, after it lost more than 1,300 feet of elevation to the catastrophic landslide and eruption of May 18, 1980, the surrounding landscape still steaming. The AtlanticThe melted dashboard of a pickup truck located on a ridge top about 14 km north of Mount St. Helens, in Skamania County, Washington, on June 18, 1980. USGSThe streets of Yakima, Washington, are dark at 3-00 p.m. after an eruption of Mount St. Helens on May 18, 1980. Volcanic ash covered the streets as people wore masks to avoid breathing the particles. The AtlanticLakes nearest to Mount St. Helens have been partly covered with felled trees for more than thirty years. This photograph was taken in 2012. WikipediaMount St. Helens erupts again, on July 22, 1980. The AtlanticSatellites in orbit and scientists on the ground still monitor the mountain and track the recovery of Mt. St. Helens. This image shows a three-dimensional view of the mountain, looking toward the southeast, as it appeared on April 30, 2015. The image was assembled from data acquired by the Operational Land Imager on Landsat 8 and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on Terra. Jesse Allen and Joshua Stevens / NASA Earth ObservatoryA memorial to those who lost their lives in the May 18, 1980, eruption of Mount St. Helens, photographed on May 18, 2010, in Washington state. Ted. S Warren/ APA tourist stops to take photos of Mount St. Helens at sunset on October 4, 2004. Andy Clark/ Reuters