The northeastern United States has been rather soggy this year. With more than two weeks still left in 2018, many locations have already posted their wettest years on record.
Here in New York City, we have received 59.68 inches of rain to date, which is 12.08 inches above average. That means 2018 now ranks among the top ten wettest years ever recorded in the Big Apple.
Much of this impressive, and still building, total came down during several heavy rain events over the course of the year. Each of these caused street and subway flooding around the five boroughs. For the northeast region as a whole, heavy precipitation events increased 55% between 1958 and 2016, according to the latest National Climate Assessment.
Scientists attribute the increase in both frequency and intensity of heavy rain events to climate change. As greenhouse gases warm the atmosphere, the air is able to “hold” more water vapor. More specifically, according to the Clausius–Clapeyron relation, for every increase of 1°F, the saturation level of the atmosphere increases by about 4%. That means there is more water vapor available in the air to condense and fall as precipitation.