Hurricanes rare in isolated Hawaiian Islands

HONOLULU – Hurricanes in Hawaii are surprisingly rare, partly due to a quirk of geography that puts the islands just out of the worst swath of danger.

While there are usually four or five tropical cyclones in the central Pacific Ocean each year, fewer than 10 have gotten within 200 nautical miles of the islands since records began to be kept in 1950, according to the Central Pacific Hurricane Center.

There are three main reasons Hawaii is so seldom hit with hurricanes, despite being in an ocean where they are frequent.

The first is Hawaii’s fortuitous location within the flow of the easterly trade winds. Even as hurricanes move toward the islands, when they get close, these prevailing winds push them westward and away.

That’s what’s happening with Hurricane Lane. As it gets close to the island of Oahu, it’s making the usual turn to the west, mostly avoiding the islands, despite the sometimes devastating winds and rain it brought to the Big Island and Maui.

A second reason is simply that the Pacific Ocean is very large, and Hawaii is very small.

“It’s the proverbial needle in the haystack,” said Jeff Weber, an atmospheric scientist at the University Corporation for Atmospheric Research.

Another reason is ocean temperature. Tropical storms can only form and continue in areas where the ocean surface temperature is 80 degrees or above. The Hawaiian Islands are the visible tops of massive volcanos, most of which lie below the surface. The temperature of the water at the ocean floor, which can be as deep as 31⁄2 miles around the islands, is about 35 degrees.