Visible satellite image of Hurricane Erin off the East Coast and a zoomed inset of smoke pouring from the Twin Towers in New York City on Sept. 11, 2001.

(NASA)

At a Glance

On the morning of Sept. 11, 2001, a hurricane was well off the East Coast.One can only speculate how history may have been different if it raced up the East Coast.

On Sept. 11, 2001, as terrorist attacks were unfolding in New York City, the Pentagon and near Shanksville, Pennsylvania, a hurricane was hovering off the Northeast seaboard.

In one of the most chilling weather images ever taken, both , about 500 miles east-southeast of New York, and the smoke plume from the World Trade Center Twin Towers about two hours after the first tower was hit was captured in a NASA satellite image.

The previous morning, a cold front swept through the East Coast with rain and thunderstorms. Crystal clear, cool weather followed on the morning of Tuesday, Sept. 11, accompanied by light northwest winds.

was never an East Coast landfall threat, as the cold front and increased westerly winds aloft gave a final east, then northeast shove to Erin. Erin did generate large swells which eventually reached the East Coast.

The Sept. 11, 2001, morning surface and upper-air weather depiction. Path history of Hurricane Erin is also shown, with red corresponding to hurricane intensity, and purple corresponding to Category 3 intensity.

(Hurricane track data: NOAA/NHC)

What If ...

Those specializing in alternative history can speculate how world events would have turned out differently if Hurricane Erin would've threatened the Northeast in September 2001.

We'll just mention here that the idea isn't far-fetched.

According to NOAA's database, have tracked within 60 nautical miles of New York City in records dating to the Civil War.Six of those have occurred in September.

Among them was in September 1985and the infamous in September 1938.

In the years after the Sept. 11 attacks, several hurricanes have reached the Northeast, some in September:

hammered the Washington D.C. metro area, among others.)triggered storm surge flooding just below the destructive threshold for New York Citytriggered massive storm surge flooding in New York City, New Jersey, and elsewhere.

Mosaic radar image showing the center of Hurricane Irene just south of Cape May, New Jersey, on Aug. 28, 2011, at 3:02 a.m. EDT.

(NOAA/NWS)

As we saw with Sandy, all you need is a strong enough area of high pressure aloft over the western Atlantic Ocean to steer the hurricane into the East Coast, rather than allowing it to "recurve" safely out to sea.

In a strange coincidence, almost exactly 10 years after the attacks, was spinning in almost the same location on Sept. 9, 2011. As with Erin,before reaching the East Coast.

Then almost exactly 20 years after the attacks, Hurricane Larry was also spinning in a similar location, a bit farther east than both Erin and Katia.

Locations of Hurricanes Erin, Katia and Larry on Sept. 11, 2001, Sept. 9, 2011, and Sept. 10, 2021, respectively.

(Track data: NOAA/NHC)

Two of the four hijacked planes on Sept. 11, 2001, took off from Boston's Logan Airport, and one each took off from Newark-Liberty and Dulles Airports.

It's fair to assume that a significant number of flights to and from the major Northeast hubs would've been canceled if Hurricane Erin had threatened the East Coast in September 2001.

Some of those airports may have even been forced to close for a while.

Whether a Hurricane Erin East Coast track would've thwarted, or merely delayed, the hijackers' plans to carry out the worst terrorist attack on U.S. soil will likely never be known.

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