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

Medical Examiner

The Most Terrifying Thing About Ebola 

The disease threatens humanity by preying on humanity.

I Bought the Huge iPhone. I’m Already Thinking of Returning It.

Scotland Is Just the Beginning. Expect More Political Earthquakes in Europe.

Students Aren’t Going to College Football Games as Much Anymore

And schools are getting worried.

Two Damn Good, Very Different Movies About Soldiers Returning From War

The XX Factor

Lifetime Didn’t Think the Steubenville Rape Case Was Dramatic Enough

So they added a little self-immolation.

Politics

Blacks Don’t Have a Corporal Punishment Problem

Americans do. But when blacks exhibit the same behaviors as others, it becomes part of a greater black pathology. 

Why a Sketch of Chelsea Manning Is Stirring Up Controversy

How Worried Should Poland, the Baltic States, and Georgia Be About a Russian Invasion?

Trending News Channel
Sept. 19 2014 1:11 PM Watch Flashes of Lightning Created in a Lab  
  News & Politics
Weigel
Sept. 20 2014 11:13 AM -30-
  Business
Business Insider
Sept. 20 2014 6:30 AM The Man Making Bill Gates Richer
  Life
Quora
Sept. 20 2014 7:27 AM How Do Plants Grow Aboard the International Space Station?
  Double X
The XX Factor
Sept. 19 2014 4:58 PM Steubenville Gets the Lifetime Treatment (And a Cheerleader Erupts Into Flames)
  Slate Plus
Tv Club
Sept. 21 2014 1:15 PM The Slate Doctor Who Podcast: Episode 5  A spoiler-filled discussion of "Time Heist."
  Arts
Brow Beat
Sept. 21 2014 2:00 PM Colin Farrell Will Star in True Detective’s Second Season
  Technology
Future Tense
Sept. 19 2014 6:31 PM The One Big Problem With the Enormous New iPhone
  Health & Science
Bad Astronomy
Sept. 21 2014 8:00 AM An Astronaut’s Guided Video Tour of Earth
  Sports
Sports Nut
Sept. 18 2014 11:42 AM Grandmaster Clash One of the most amazing feats in chess history just happened, and no one noticed.