Hawaii Braces For Rare Hurricane, Another One Will Then Harrass State

Hurricane Iselle spinning toward Hawaii yesterday.  

Hurricane Iselle was still making a beeline for the Big Island of Hawaii Thursday morning, and it could become the first hurricane on record to hit that particular island in the Hawaiian chain.

Hurricane Julio is coming right behind Iselle, but it looks like Julio will curve north of the islands, but will probably come close enough to cause some more wind and more flooding

That two tropical systems would threaten Hawaii in one week is unprecedented, notes Mashable.

Hurricanes thrive on warm ocean water, and die when the water gets cooler.

Hawaii is normally sort of protected by normal ocean currents that keep the water surrounding the island kind of on the cool side. So hurricanes usually, but not always,  die before they reach Hawaii.

Ocean temperatures in much of the Pacific Ocean, including in areas near Hawaii, are warmer than average, which gives tropical storms a kick in the pants to stay alive.

In fact, the forecast with Iselle kept getting worse over the past few days.  As Iselle headed toward colder water, it was expected to weaken into a tropical storm. But shifting winds in the upper atmosphere that usually tear hurricanes apart didn't materialize yesterday, so Iselle actually strengthened a bit.

Now, it's entering cooler water and those upper level winds, called shear, are starting to affect Iselle. It may or may not be a hurricane by the time it reaches the Big Island, but whether it is a hurricane or just close to it is just a matter of semantics.

Since Hawaii doesn't usually get such strong winds, trees and structures aren't able to withstand winds of 50, 60, 70, or 80 mph like in some other areas of the United States. So wind damage might be worse than if it hit, say, Florida, where there are somewhat stronger building codes.

Or, buildings that were up to code in Hawaii might have issues nobody knows about because there hasn't been strong winds in such a long time.

The rain is going to cause flooding too. Water will rush down the steep slopes of the islands. They're expecting 5 to 8 inches of rain in many areas, with some spots reaching a foot. The flash flooding and landslides might be terrible.

As I said, this might end up being the first time the Big Island of Hawaii, the easternmost one, is hit directly by a hurricane.

More western islands in Hawaii, where the water temperature is a little warmer, have been hit by hurricanes before.

The most noteworthy was Iniki in 1992, which hit the island of Kauai with 140 mph winds. It killed six people and caused widespread damage.

Here's a video of Iniki lashing Kauai Island in Hawaii in 1992. It's from a Discovery Channel show called "Destroyed in Seconds." After the narrator sets up the scenario, things get scary 45 seconds into the video: