Irene Nearly Twice the Size of Typical Hurricane

Hurricane Irene is not the fastest nor the strongest storm in recent memory. Instead, it is her size that has helped to turn her into such a star over the past 20 hours. 

“You only have to look at the weather maps to understand how big this storm is and how unique it is,” New York Mayor Bloomberg said at a news conference Friday, “and it’s heading basically for us.”

But just how unique is she in terms of size? Typical hurricanes are about 300 miles wide, according to the National Weather Service. Irene is currently almost twice that, extending 290 miles from her center, and thereby taking up about one third of the East Coast. Not only is she big – she’s growing quickly. Her girth has expanded nearly 200 miles since Tuesday, according to Rob Gutro, NASA's deputy news chief. By Sunday she could be much bigger.

Here's what she looked like Friday afternoon:

In terms of purely physical reach, this makes Irene wider than Hurricane Katrina, which extended about 400 miles across, according to Tulane University. Here's what Katrina looked like in 2005:

Irene's size makes her most comparable to 2004's Hurricane Ivan, which itself was often likened to the size of Texas (about 660 miles across at its most distant points). Here's Ivan:

Gutro, who posts all the hurricane satellite images on NASA’s site, cautions, however, that size isn't everything when it comes to indicating a storm's power or the likely damage it will cause. Hurricane Andrew of 1992 was one of the most damaging hurricanes of the century, despite being relatively small. A massive hurricane, likewise, can be relatively weak. The only thing that a larger size definitely indicates is that more counties have opportunities to grow alarmed.

Here's a sequence of what Andrew looked like: