This past May has set another record for climate extremes in the U.S. While California continues to languish in drought, the NOAA reported that the contiguous U.S. as a whole had the wettest month since record-keeping began 121 years ago. An average of 4.36 inches of rain and snow fell on the lower 48 states, and NOAA climate scientists have calculated that this amounts to over 200 trillion gallons of precipitation in four weeks.
A series of stalled storms contributed to massive rainfall in the central U.S., which created devastating flooding in Texas and Oklahoma and claimed dozens of lives. A state of emergency was declared across 37 cities in Texas as rain deluged areas south of Austin to Houston. Enough rain fell in Oklahoma to take the parts of the state from “exceptional” drought conditions—the most severe category—to absolutely no drought whatsoever in just four weeks. This extraordinary phenomenon was described by NOAA climate scientist Jake Crouch as “like one disaster ending a catastrophe.”
The national average rainfall for the lower 48 states was 4.36 inches, a full 1.45 inches above average, beating out the previous wettest month in U.S. history, which occurred in October 2009, when 4.29 inches fell. According to Mashable, Texas state climatologist John Nielsen-Gammon has said that “such an extremely wet month might have a recurrence period of about every 2,000 years, assuming the climate was stationary.” But, given the effects of global warming, the climate is far from stationary—and we are likely to see more such months like this in an increasingly hot, moist atmosphere.
Moreover, we’re also going to see more extremes in the other direction—as evidenced by the ongoing drought in California, and the remarkably dry May that was experienced in the North Eastern U.S.
Images via TexanGentsCode on Twitter, and NOAA