Flood in Grafton County, New Hampshire

On the afternoon of May 15, 2026, minor river flooding occurred along the Pemigewasset River at Plymouth, New Hampshire, driven by basin-wide rainfall averages of 2.75 inches across the Pemigewasset Basin. Water levels rose quickly during the morning, reaching the 13.0-foot flood stage by early afternoon and cresting at approximately 13.1 feet. The brief crest caused minor lowland inundation and shallow water accumulation near Plymouth State University parking areas in Grafton and Belknap Counties before the river fell back below flood stage later that afternoon. No structural damage was reported.

On May 15, 2026, a widespread soaking rainfall event delivered heavy precipitation across the White Mountains region, producing basin-wide averages of 2.75 inches in the Pemigewasset Basin and approximately 3.25 inches in the Upper Saco Basin. Rapid runoff from the heavy rain caused river levels to rise quickly above flood stage in both New Hampshire. The resulting minor flooding inundated low-lying areas and riverside campgrounds in Grafton and Carroll Counties. While no structural damage was reported, the sudden rise in water levels disrupted early-season recreational activity before both rivers receded back into their banks.