The good news is that Hurricane Lane has been downgraded to a Category 4 hurricane. The bad news is that it is still heading straight for the Hawaiian islands.  The storm’s outer bands have been pounding parts of Hawaii’s Big Island with rain Thursday morning, triggering landslides and threatening serious flooding. The hurricane is the first major cyclone to make landfall in the state in 26 years when Hurricane Iniki caused around $3.1 billion of damage and six deaths. Like Hurricane Lane, Iniki was also a Category 4 hurricane and was the most powerful hurricane to strike the U.S. state of Hawaii in recorded history.

Why are hurricanes so rare in Hawaii? One reason has to do with the size of the islands. In the largest ocean in the globe, the islands are relatively small. The state of Florida is roughly six times larger in area, for example.  Compared to Florida and the US East Coast, the Hawaiian islands are a small target. 

The wind patterns around the islands also provide some protection. Popular Science quotes Brian McNoldy, a meteorologist at University of Miami who notes that: “The major reason that Hawaii doesn’t normally get major hurricanes nearby is that there’s a strong subtropical high-pressure system that sits just to the north, and that acts to steer [storms] straight west.” McNoldy says.

Unfortunately for Hawaii, right now that system isn’t doing what it normally does. “For the last 1-2 months that high pressure is a little weaker than normal and it’s a little farther west than normal,” McNoldy says.

Also, the waters around the islands this year are unseasonably warm, adding potential energy to the storm.

“Hawaii rarely gets hurricanes, so when they do its really big deal because they’re not really built for it,” McNoldy says.