PITTSBURGH, PENNSYLVANIA—Heavy rains in western Pennsylvania last month flooded Meadowcroft Rock Shelter, one of the earliest archaeological sites in North America. In the 1970s, James Adovasio, then of the University of Pittsburgh, excavated the site and found that humans had lived there thousands of years earlier than had been thought possible. Now director of Mercyhurst University’s Archaeological Institute, Adovasio will re-excavate portions of the site affected by the flooding. “It just happens that the time frame (with the damage) coincides with some of the most important times in the history of people in eastern North America. We’ll be able to better understand these periods. But given our druthers, we certainly wouldn’t have done this right now,” he said.