Hurricane Isaias shattered the peace of one of the quietest Atlantic hurricane seasons on record as it grew into and near Destin, Fla., late on Oct. 9.

The Category 2 hurricane’s storm surge reach 5.6 feet at Panama City Beach as it crossed coast. Forecasters warned of over a large portion of thesoutheastern U.S. and flooding rain as the storm moved inland toward the Appalachian Mountains.

Isaias for the latest-forming first hurricane of a season on record. To understand why it was able to strengthen into a hurricane when no other storms in the first two-thirds of the 2026 season did, let’s take a look at what was going on in the atmosphere.

Hurricane Isaias faced strong winds as it moved across warm Gulf waters. The wind influence is evidence in the storm’s lopsided rain bands, primarily pushed to its northeast, on Oct. 8, 2026.

As an who has studied hurricanes for years, I can tell you that wind shear and the climate phenomenon known as El Niño both play important roles.

Why the 2026 season had such a quiet start

Usually, Atlantic hurricane activity . In a typical season, the Atlantic region experiences by early October. Having no hurricanes is nearly unprecedented in the Atlantic hurricane record.

The main culprit is likely El Niño.

El Niño is that occurs every few years when ocean surface temperatures in the central and eastern Pacific Ocean heat up. That heat can influence weather around the world – including Atlantic hurricanes.

How El Niño influences weather around the world, including Atlantic hurricanes.

The 2026 by late summer, and forecasters expected to see it become El Niño events on record.

2 ways El Niño prevents hurricanes from forming

When the waters of the eastern Pacific warm substantially, they create more rising air over the eastern Pacific, and with it, more . The net effect is a current of rising air that flows northward across portions of Central America. This flow turns toward the east in the Northern Hemisphere , and it increases the westerly winds across the tropical Atlantic.

Under normal atmospheric circulation, air in the eastern tropical Pacific sinks, leaving drier air in that region, while the tropical Atlantic has moist, rising air that can fuel hurricanes. During El Niños, however, that flips – the eastern tropical Pacific Ocean is wetter, creating strongly rising air and more Pacific hurricanes, while the region where Atlantic hurricanes typically form is drier and less stormy.

Winds near the surface blowing from the east, along with winds at higher altitudes blowing from the west, create . Wind shear makes it harder for hurricanes to form because it disrupts any deep column of moisture that tries to organize into a vortex.

El Niño has another effect on Atlantic hurricane formation: With more rising air above the eastern Pacific warm waters, air tends to . Hurricanes need lots of moisture, so dry air makes it harder for one to form.

The tropical Atlantic was hit with both vertical wind shear and dry air in 2026.

Most of the in the Atlantic earlier in 2026 did so to the north of the region of vertical shear and dry air, but it is rare for storms forming at those higher latitudes to become strong hurricanes.

The hurricane storm tracks in 2026, through Oct. 8, show that most storms formed in northern areas. Typically, storms that become strong hurricanes form farther south and travel through the Caribbean. But dry air and wind shear made formation difficult in 2026 – Isaias is storm No. 9.

How Isaias formed in these conditions

So how did Isaias manage to break through?

First, Isaias did not form in the deep tropics, where many of the strongest hurricanes originate. That region is still seeing plenty of wind shear. Isaias of Mexico (also referred to as the Gulf of America) instead.

In early October, and a small region of enhanced moisture moved over the western Gulf. Both of these factors made hurricane formation more likely, and water provided fuel for the storm that formed.

Isaias organized rapidly in this environment.

But, as is often true with late-season hurricanes approaching the U.S., the jet stream is not far away. While Isaias strengthened, vertical shear also started increasing – not due to El Niño, but because the as autumn sets in.

Isaias grew into a dangerous storm, but it could have been even stronger without the effects of wind shear.

What’s ahead for Atlantic hurricane season?

The rapid emergence of Isaias is a reminder that a slow start to the hurricane season doesn’t mean a quiet end. The season does not end officially until November 30.

Atmospheric conditions often change considerably in October from what they were in July through September as temperatures fall. So coastal regions can’t let their guard down yet – the season could bring more surprises.

This article, originally published Oct. 9, 2026, has been updated with the storm making landfall.

Original article
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