This fact sheet highlights regional trends, impacts, and vulnerabilities associated with heavy precipitation in the United States, examines how climate change is amplifying heavy precipitation events, and identifies some initiatives helping to address the issue.

Executive Summary

Since the late 1950s the United States has observed an increase in heavy precipitation. Warming temperatures due to human-caused climate change has allowed the atmosphere to hold more moisture, which has been a main contributing factor to these increases. Heavy precipitation, combined with factors like aging drainage infrastructure and changing land-use (e.g., more non-permeable surfaces like asphalt), can threaten communities, economies, and human health by amplifying urban floods and flash floods. Additionally, heavy downpours impact agriculture through crop damage and soil erosion, and compromise city and state transportation systems across the country.