Characterization of peak streamflows and flooding in select areas of Pennsylvania from the remnants of Hurricane Ida, September 1–2, 2021

First posted September 7, 2023 For additional information, contact: Director, Pennsylvania Water Science CenterU.S. Geological Survey215 Limekiln RoadNew Cumberland, PA 170Contact Pubs Warehouse experienced heavy rainfall on 1 and 2, 2021, as the remnants of Hurricane Ida swept over parts State. Much eastern south-central received 5 to 10 inches rain, most fell within little more than 6 hours. Southeastern widespread, substantial flooding, city Philadelphia surrounding areas were particularly affected by flooding. U.S. Survey (USGS) streamgages registered peak streamflows record at 19 locations, 52 locations top for period an annual exceedance probability estimate least percent. During this 2021 flood event, USGS personnel made 60 streamflow measurements in using direct indirect methods. Many those verify or improve accuracy, extent, development new stage-streamflow relations operated USGS. After floodwaters receded, identified documented a total 338 high-water marks Pennsylvania, noting such things their general description, location, height above land surface, quality. these used create five flood-documentation maps selected communities southeastern that flooding because Ida. Digital datasets inundated areas, mapped boundaries, water depth are available (Stuckey Conlon, 2023).