The intensification of the strongest nor'easters.

Nor'easters are coastal extratropical cyclones that feed upon both thermal contrasts (meridional and land-ocean) and oceanic latent heat release, causing them to intensify along the U.S. East Coast. With central pressures that sometimes rival those of tropical cyclones, they represent a significant coastal hazard and are often associated with strong winds, heavy snowfall, disruption, and damage. While interest in studying the impacts of climate change on storm behavior is growing, nor'easters have historically received far less attention than tropical cyclones, largely due to challenges in documenting and categorizing these storms combined with the relatively short observational record. Here, we address these challenges by employing a cyclone tracking approach in concurrence with long-term reanalysis data to create a reliable historical database of these storms. We find a significant increasing trend in the maximum wind speeds of the most intense (>66th percentile) nor'easters. We also observe an increasing trend in hourly precipitation rates associated with these storms. Such changes have profound implications for coastal cities and shorelines, increasing the risk of coastal flooding and erosion.