A severe thunderstorm with straight-line winds damaged two historic structures within the boundaries of Keweenaw National Historical Park on July 1st. The former Calumet & Hecla Mining Company dryhouse #2 lost its entire roof and sections of exterior walls. The adjacent drill shop lost a large portion of its roof and sustained structural damage. Dryhouse #2 contains a collection of historic drill core samples that were used by Calumet & Hecla Mining Company. The drill shop is used by the local community as a curling club facility. Both buildings are contributing structures within the Calumet National Historic Landmark District. The park is working with the Midwest Regional Office to identify short and long-term measures to protect the buildings and their contents, including a substantial collection of historic drill core.