Photograph of an explosion conducted by Portland & Seattle Railway to clear way for the construction of a railroad on the Washington side of the Columbia River Gorge. The explosion sends dirt and debris into the air out of the base of a mountain. The Columbia River and the Oregon side of the gorge are visible in the background. Handwritten label at the bottom of the print reads, "Firing 30 Ton Blast Cooks, 1906, P. & S. Ry., June 13, 10:35am, 1300 feet away."