Hurricane Erin is huge, how does it compare to previous storms?
The storm’s footprint measured nearly 900 km wide on Thursday
Hurricane Erin grew to a scale-topping Category 5 this past weekend. Considerably weaker now than it was at its peak, Erin remains an immense storm.
The system’s wind field grew to nearly 900 km wide as it swirled through the western Atlantic Ocean on Thursday, placing its sheer size among the upper echelon of hurricanes to pass through this part of the basin.
Here’s a look at how Hurricane Erin compares to large storms in the past, including systems like Fiona and Katrina.
DON’T MISS: An inside look at Hurricane Erin’s astounding rise to Category 5
Erin is a very large hurricane
The U.S. National Hurricane Center (NHC) found on Thursday that Hurricane Erin’s tropical storm force (63-118 km/h) winds extended up to 520 km from the centre of the storm.
All told, Erin’s wind field stretched nearly 900 km across as it passed between North Carolina and Bermuda.
For perspective, that’s similar to the distances between Toronto–Moosonee, Ottawa–Halifax, and Vancouver–Edmonton. If the storm were in the Gulf of Mexico exactly as it stands today, its strong winds would almost stretch from Miami to New Orleans.
Erin compared to past storms
Hurricanes usually don’t grow this big.
“Comparing Erin with systems around the same intensity and in similar locations over the past couple of decades,” the NHC wrote on Thursday, “indicates that it is around the 90th percentile in size.”
Several hurricanes in recent memory were notable for their immense size.
Hurricane Fiona hit the Maritimes in 2022, and Hurricane Sandy struck the U.S. East Coast in 2012. Both storms saw their wind fields expand to nearly 1,500 km across by the time each storm made landfall, exacerbating the extensive damage they caused.
Hurricane Katrina’s hurricane force winds extended nearly 200 km from the eye of the powerful storm, pushing a very large storm surge into the northern Gulf Coast, including New Orleans.
Why some hurricanes grow so large
Lots of factors have played into Erin’s steady growth since it formed in the eastern Atlantic back on Aug. 11.
The hurricane underwent numerous eyewall replacement cycles (ERC) after its rapid intensification to Category 5 status on Saturday, Aug. 16. Each ERC can dramatically expand the storm’s size.
Tropical systems also tend to grow in size as they gain latitude and begin to lose their tropical characteristics.
Erin is forecast to become a post-tropical cyclone by Saturday morning, meaning it’ll transition to an ‘everyday’ type of low-pressure system that draws energy from upper-level winds rather than thunderstorms at the centre of the system. Storms expand during this process. This phenomenon was responsible for both Fiona and Sandy growing so large just before landfall.