What is causing more extreme precipitation in northeastern U.S.?

From Maine to West Virginia, the Northeast has seen a larger increase in extreme precipitation than anywhere else in the US. Prior research found that these heavy rain and snow events, defined as a day with about two inches of precipitation or more, have been 53 percent higher in the Northeast since 1996. A new study finds that hurricanes and tropical storms are the primary cause of this increase, followed by thunderstorms along fronts and extratropical cyclones like Nor’easters.