Long Island Got as Much Rain This Week as It Usually Does All Summer

The Citizen's Guide to the Future
Aug. 13 2014 1:35 PM

America Is Under Water, Literally

It’s been a very, very wet week in America.

After causing flash floods in Detroit and Baltimore on Tuesday, Wednesday’s deluge broke a statewide record in New York, according to the National Weather Service:

Advertisement

That’s more rain than Long Island normally sees in an entire summer.

The previous record was set less than three years ago when Tannersville, New York, received 11.6 inches during Hurricane Irene, unleashing catastrophic flooding throughout the Catskills region.

Over the past day or so, a tropical conveyor belt has sent moisture streaming northward and compressed it, with storms riding along wind currents streaming into a slow-moving storm system that’s lingering over the Great Lakes. The effect has been similar to a slow-moving tropical storm, only with less wind at the coast. Although floods were predicted, with this kind of system, it’s kind of impossible to know exactly where they would occur.

Had Wednesday’s rain swath shifted just 50 miles or so to the West, I’d be talking instead about one of the biggest flash floods in New York City history. (The most rain that’s ever fallen in a single day in Central Park was a measly 8.28 inches back on Sept. 23, 1882. The New York Times account of that storm is amazing.)

As it was, the storms carved a path of heavy rain right through the heart of the urban Northeast:

The impressive Northeast rainfall totals were produced by an atmospheric process known as “training” (as in, choo-choo). Individual storm cells line up like a row of box cars, hitting the same areas over and over and over again. Training isn’t uncommon during times when slow-moving tropical flow is present, but usually it lasts only a few hours. In the case of these rainstorms, the train kept coming for the better part of a day.

Scenes from the floods have been dramatic:

Seattle:

Phoenix:

Detroit:

Baltimore:

Long Island:

There was so much water in Long Island this morning, there were white caps on the Sunrise Highway, one of the main commuting routes into New York City. Seattle’s intense rains were caused by sporadic thunderstorms moving across the Northwest, an area of intensifying drought. At one point on Tuesday, remarkably, there was a flash flood watch at the same time and place as a Red Flag warning for wildfires in Washington State.

This week’s floods are a glimpse of a changed climate. As the atmosphere warms due to human greenhouse gas emissions, it can hold more water vapor. That means rainstorms have become more intense in recent years, and are expected to continue getting more extreme in the coming decades. This year’s National Climate Assessment showed that extreme rainfall events are increasing quickest in the Northeast. On Tuesday, NOAA released new data showing that so far in 2014, the weather pattern over America has been one of the most extreme on record.

Earlier this year, Pensacola, Florida, experienced an equally remarkable episode of training—racking up more than two feet of rain in little more than a day—with devastating consequences.

The National Weather Service warns that the flash flooding event isn’t over yet. Extremely heavy rain continues across much of New England, where more flooding is likely during the day on Wednesday.

The Washington Post has a comprehensive breakdown of the meteorology behind the series of flash flood events, focusing on the Baltimore area.

Future Tense is a partnership of SlateNew America, and Arizona State University.

Eric Holthaus is a meteorologist who writes about weather and climate for Slate’s Future Tense. Follow him on Twitter.

TODAY IN SLATE

History

Slate Plus Early Read: The Self-Made Man

The story of America’s most pliable, pernicious, irrepressible myth.

Rehtaeh Parsons Was the Most Famous Victim in Canada. Now, Journalists Can’t Even Say Her Name.

Mitt Romney May Be Weighing a 2016 Run. That Would Be a Big Mistake.

Amazing Photos From Hong Kong’s Umbrella Revolution

Transparent Is the Fall’s Only Great New Show

The XX Factor

Rehtaeh Parsons Was the Most Famous Victim in Canada

Now, journalists can't even say her name.

Doublex

Lena Dunham, the Book

More shtick than honesty in Not That Kind of Girl.

What a Juicy New Book About Diane Sawyer and Katie Couric Fails to Tell Us About the TV News Business

Does Your Child Have Sluggish Cognitive Tempo? Or Is That Just a Disorder Made Up to Scare You?

  News & Politics
History
Sept. 29 2014 11:45 PM The Self-Made Man The story of America’s most pliable, pernicious, irrepressible myth.
  Business
Moneybox
Sept. 29 2014 7:01 PM We May Never Know If Larry Ellison Flew a Fighter Jet Under the Golden Gate Bridge
  Life
Dear Prudence
Sept. 29 2014 3:10 PM The Lonely Teetotaler Prudie counsels a letter writer who doesn’t drink alcohol—and is constantly harassed by others for it.
  Double X
Doublex
Sept. 29 2014 11:43 PM Lena Dunham, the Book More shtick than honesty in Not That Kind of Girl.
  Slate Plus
Slate Fare
Sept. 29 2014 8:45 AM Slate Isn’t Too Liberal, but … What readers said about the magazine’s bias and balance.
  Arts
Brow Beat
Sept. 29 2014 9:06 PM Paul Thomas Anderson’s Inherent Vice Looks Like a Comic Masterpiece
  Technology
Future Tense
Sept. 29 2014 11:56 PM Innovation Starvation, the Next Generation Humankind has lots of great ideas for the future. We need people to carry them out.
  Health & Science
Medical Examiner
Sept. 29 2014 11:32 PM The Daydream Disorder Is sluggish cognitive tempo a disease or disease mongering?
  Sports
Sports Nut
Sept. 28 2014 8:30 PM NFL Players Die Young. Or Maybe They Live Long Lives. Why it’s so hard to pin down the effects of football on players’ lives.