The result is that during most of the season, hurricanes head north-northwest.
Normally the trade winds blow steadily from the east, scooting Pacific storms along a track that passes well south of Hawaii.
Flossie's close approach was a rare exception, Tanabe said, as were the three hurricanes that got close to Kauai.
"Iniki and Iwa hit late in the season, when we didn't have as persistent trade winds," he said.
"We had a surface low [a region of low atmospheric pressure] to the west and weak to nonexistent trade winds over the islands, which allowed the hurricanes to curve to the north."
And Iniki and Iwa were especially rare, because normally a strong summer jet stream protects the islands from storms that veer north.
These upper-level jet stream winds tend to rip the tops off the hurricanes and disperse them.
"You're kind of cutting the storm in two," Tanabe said.
Shelter in Place
When hurricanes do strike, Hawaii is vulnerable to catastrophic impacts.
"We're isolated," Tanabe said. "If we require outside assistance, it's going to take a long time to get here, especially if our ports or airports are damaged.
"We can't just get in a car and drive somewhere," he continued. "We have to shelter in place."
Heavy rains can also be a problem.
"Parts of the islands get 400 inches [1,000 centimeters] of rain per year," Tanabe said.
"We can handle quite a bit of rainfall because we're used to it. But we can't handle it as well if it all comes at once."
What's more, when a hurricane like Flossie passes south of the islands, it produces storm conditions on the islands' dry sides.
In addition to dumping heavy rains, such storms batter ocean reefs to the south that are unaccustomed to heavy surf.
"In winter the Hawaiian islands get big surf on [the north] side, so the reefs there are robust," said Randy Kosaki, research coordinator for the Papah'naumoku'kea Marine National Monument in Hawaii's northeastern islands.
(Related: "Hurricanes Heal Reefs in Surprising Cases" [July 2, 2007].)
"The south shores are more sheltered."
The result is that these reefs produce the best coral, but they also take a pounding when the occasional hurricane passes on their side.
"When you get big surf coming from an odd direction," Kosaki said, "you see a lot of broken coral."
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