The Atlantic is still carrying the scars of Hurricane Erin.
In the storm’s wake, satellite data shows a broad swath of the ocean several degrees cooler than it was even a week ago.
This is a striking reminder of how a powerful Category 5 hurricane like Erin doesn’t just churn the air, it stirs the sea.
Erin grew into an unusually large system sending tropical storm–force winds across nearly 600 miles of ocean off the Southeast U.S. and whipping up waves along with upwelling cooler deep ocean water beneath the storm’s surface.
How hurricanes cool the ocean
When a storm like Erin spins over the sea, its fierce winds mix the ocean from top to bottom. This turbulence draws colder, denser water up from the depths in a process called upwelling. Hurricanes thrive in warm water, typically above 79°F, but once cooler water rises to the surface, the fuel supply is cut off.
Studies show that hurricanes can drop sea surface temperatures by 3.5 to 11°F, depending on their speed and width. In slow-moving giants like Erin, the effect can be even more dramatic—sometimes more than 14°F of cooling. The cold pool left behind covers hundreds of miles and has lingered for days.
Can it Prevent Future Storms?
In the short term, yes. A trailing storm that tracks over the same cooled footprint often weakens or fails to intensify. History offers storm-on-storm examples like Hurricane Jeanne that weakened when it crossed the cooler waters churned up by Hurricane Frances just days earlier in 2004.
But this protection is only local and temporary. No tropical systems are expected to develop or pass through Erin’s cool pool before sea temperatures return to equilibrium.
Typically, the cooled patch of water lasts 5 to 10 days, and in the case of large or slow-moving storms, it can persist for two weeks or longer. Over time, sunlight reheats the surface, and currents mix the layers, erasing the hurricane’s footprint.