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Penn Today

Strongest nor’easters getting stronger

Research from Professor Michael Mann and Ph.D. students Annabelle Horton and Mackenzie Weaver shows that as the worst of these East Coast winter storms intensify, so does their destructive potential—a facet that current coastal risk assessments often ignore.

July 15, 2025
A map showing increase in nor’easters.

In 2010, a historic nor’easter dumped more than two feet of snow on Philadelphia, forcing climate scientist Michael Mann to cancel a guest lecture at Penn. Now a Presidential Distinguished Professor and Vice Provost for Climate Science, Policy, and Action at Penn, Mann has turned that snowed-out moment into a research focus. In a new study published in Proceedings of the National Academy of Sciences with PhD students Annabelle Horton and Mackenzie Weaver, the team finds that while nor’easters have become less frequent since 1940, the most powerful among them are intensifying - with stronger winds and heavier precipitation - highlighting the growing impact of climate change on extreme weather. Read more at Penn Today.

Source:
Penn Today
Topics:
Climate
Nature