Hurricanes

Hurricanes

[Illustration: Hurricane]

 

For well over an hour on September 11, 1992, Kaua‘i’s north shore residents endured ferocious winds as they huddled in shelters throughout the island.  They could hear windows being smashed by the airborne debris that filled the air and crashed violently into buildings. 

Sometimes a whole roof would detach and lift upward in one large piece before breaking up in the vortex of wind.  Entire houses were blown off their foundations.

Then suddenly the wind stopped, and some people went outside.  It was still cloudy all around, but straight above there was pure blue sky, which was a welcome sight amidst all the destruction.  The hurricane had not passed, however, but instead was actually directly overhead!  They were right in the middle of the hurricane’s eye! 

Within minutes, as the hurricane’s eye moved past, the full force of the hurricane was felt again, this time all at once in a devastating rush of wind with gusts well more than 100 miles per hour (161 km/hr). 

Because the wind was now going in the opposite direction, structures that had been weakened to the point of collapse by the first half of the hurricane were now quickly finished off as the destruction continued.

Given the many hurricanes that roam across the Pacific each year, and the numerous hurricanes that have hit the Hawaiian Islands in historic times, it is likely that the ancient Hawaiians were quite familiar with these infrequent but massive and devastating storms. 

A Hawaiian proverb states, “O ka makani ke ala o ka ‘ino.” (“Wind is the source of storms.”)[i]

 

Anatomy of a Hurricane

When a tropical storm has winds that reach 74 miles per hour (119 km/hr) it becomes a hurricane, an organized system of thunderstorms whirling around a low-pressure center.  Hurricanes are about 300 miles (483 km) across, on average, but not usually more than 9.5 miles (15.3 km) high.

 

Formation of a Hurricane

For a hurricane to form there needs to be a source of rotation for the air—that source is the Earth’s rotation.  Air tends to curve away from the equator and toward the poles, forming a low-pressure area.  Air is drawn toward this low-pressure center, which becomes the eye of the hurricane, and may be 10 to 40 miles (16 to 64 km) across. 

As more air is drawn into the hurricane, the air has no place to go but up, sometimes to nearly 50,000 feet (15,240 m).  The rising moist air moves out the top, further reducing pressure in the eye, which then draws in more surface air in an increasing cycle that continues to fuel the storm. 

During the June to November hurricane season, an average of five storms each year reach the vicinity of the Hawaiian Islands. 

 

Hurricane ‘Iniki—September 11, 1992

In 1992, the eye of Hurricane ‘Iniki passed directly over Kaua‘i.  ‘Iniki began brewing far southeast of the Hawaiian Islands.  The winds within the hurricane continued to grow to more than 100 miles per hour (161 km/hr) as the whole hurricane slowly moved north-northwest at about 20 miles per hour (32 km/hr).  Eventually the path of the hurricane turned due north and the hurricane made a direct hit on Kaua‘i

As Hurricane ‘Iniki proceeded over the island of Kaua‘i, a ferocious gust of wind within the hurricane was clocked at 227 miles per hour (365 km/hr), a measurement that was taken by the Navy’s Mākaha Ridge radar station.  Soon after that digital readout was sent, the wind gauging equipment was blown off the mountain!

 Property damage due to Hurricane ‘Iniki totaled more than three billion dollars, including damage to over 70% of Kaua‘i’s homes.  In all, about 14,000 homes and apartments were damaged, including 1,421 that were completely destroyed. 

The community of Princeville topped the list with 279 homes destroyed.  At the time of the hurricane there were 8,200 hotel, condo, and bed and breakfast rooms on Kaua‘i, and ‘Iniki shut down 90% of them.  It was a rough time for many island residents.

  The natural landscape of Kaua‘i was also changed by Hurricane ‘Iniki, and there were long-term effects on the island’s native flora and fauna.  Much of the native forest canopy was stripped of its leaves as well as the fruit and flowers that forest birds depend on for food.  Can you imagine those poor little birds hiding as the hurricane winds blew? 

[Photograph: Native forest bird (e.g., feeding on flower)]

 

The hurricane didn’t leave a lot of food for the honeycreeper species that depend on flower nectar.  Two such species are the small, red ‘apapane (Himatione sanguinea), and the crimson colored ‘i‘iwi (Vestiaria coccinea).  The ‘i‘iwi’s long, down-curving bill fits perfectly into the long cup-shaped flower of the native lobelias. 

Some fruit-eating forest bird species such as the honeycreeper ‘ō‘ū (Psittirostra psittacea) and kāma‘o (Myadestes myadestinus, Large Kaua‘i thrush) may have already been extinct before Hurricane ‘Iniki, but if they weren’t, the storm’s reduction of the food supply may have dealt the final blow.  The last sighting of the ‘ō‘ō‘ā‘ā occurred in Kaua‘i’s Alaka‘i Swamp in 1987.

The endangered puaiohi (Myadestes palmeri, small Kaua‘i thrush) was also near extinction, but the species survived and now captive propagation efforts hold hope for saving the bird. 

Researchers remain particularly concerned about five extremely endangered forest birds, the Kaua‘i ‘akialoa (Hemignathus procerus), Kaua‘i nuku pu‘u (Hemignathus lucidus hanapepe), kāma‘o (Myadestes myadestinus), ‘ō‘ō ‘ā‘ā (Moho braccatus), and ‘ō‘ū (Psittirostra psittacea), all of which were already on the verge of extinction when the hurricane hit Kaua‘i.  None of them have been seen since Hurricane ‘Iniki.

Hurricanes That Have Hit the Hawaiian Islands

Hurricanes are not a new experience for Kaua‘i.  Hurricane Hiki passed just north of the island in 1950, bringing 70 mi/hr (113 km/hr) winds.  Hurricane Nina caused $100,000 damage on November 30, 1957.  Then Hurricane Dot passed over the island in 1959, bringing winds well over 100 mi/hr (161 km/hr) and causing six million dollars in damage. 

On November 3, 1982 Hurricane ‘Iwa passed between Kaua‘i and Ni‘ihau, bringing gusts of wind with speeds of more than 100 miles per hour (161 km/hr) and causing damages totaling 239 million dollars.

Hurricanes hit the other Hawaiian Islands as well.  An unnamed hurricane hit Hawai‘i Island, Maui, and Moloka‘i on August 9, 1871, causing $10,000 in damage.  On July 23, 1986, Hurricane Estelle caused two million dollars of damage on Hawai‘i Island, Maui, and O‘ahu.

 

Satellites and Supercomputers

The new GOES-9 satellite, at a cost of 200 million dollars, now provides forecasters with an accurate view of approaching hurricanes.  The satellite is in high, stationary orbit, remaining right over a spot on the equator about 1,900 miles (3,058 km) southeast of the Hawaiian Islands, providing continuous coverage of the central and eastern Pacific Ocean. 

Scientists are using new supercomputers to predict hurricane movement with much better accuracy than before.  Hurricanes result from high concentrations of heat in the lower tropical atmosphere, leading some researchers to theorize that global warming may cause an increase in the frequency and intensity of hurricanes. 

Hawaiian residents are well advised to have emergency provisions, and take other precautions to prepare for the unfortunate possibility of another strong hurricane passing over the Hawaiian Islands.

[Photograph: After ‘Iniki (showing devastation)]



[i]p. 264, Pukui, Mary Kawena.  ‘Ōlelo No‘eau: Hawaiian Proverbs & Poetical Sayings.  Honolulu: Bishop Museum Press, 1983.  Proverb 2422.