Hawaii's first hurricane in 23 years slammed into the state's northwestern islands Tuesday night with winds of 110 miles per hour, killing a Navy seaman, sending more than 6,700 coastal residents from their homes, and shutting down power and communications networks.

At least six civilians and four sailors were reported injured as Hurricane Iwa swirled over the Pacific chain, touching down on the islands of Kauai and Niihau.

At sea, one Navy crewman was flung overboard from a destroyer and swam two miles to shore with a broken hand and leg.

On land, the furious winds and rains tore off roofs, doubled over palm trees, flooded streets, littered roads with downed telephone and power lines and flattened sugar cane fields and crops of banana trees.

Gov. George R. Ariyoshi, who flew to Kauai to tour the most heavily stricken areas, said he was "shocked at the extent of the damage" and pledged to seek state and federal relief funds. An initial estimate of the damage on Kauai was $20 million, almost four times the amount of damage left by Hurricane Dot in August, 1959.

The island of Oahu, home to the capital city of Honolulu, was some 125 miles southeast of the storm's center but still was hit with 80 mph winds. Flooding, broken windows and roofs and about 1,000 evacuations were reported. Two police cars were washed into the ocean and a Honolulu city bus was knocked off a highway by a giant wave. There were no injuries in the incident.

The naval death and injuries were aboard the USS Goldsborough, a guided-missile destroyer that had joined 12 other vessels leaving Pearl Harbor on Tuesday to avoid the storm.

Ships are thought to be safer at sea during a storm.

Two Coast Guard ships with no one aboard sank before they could be taken to a safe haven.

A Navy spokesman said the 4,800-ton Goldsborough was caught in the hurricane winds just outside the port. One of the injured was Lt. (j.g.) Ray Beard, who was listed in satisfactory condition after swimming two miles to safety with a broken hand and leg.

The identity of the seaman who was killed and the circumstances of his death were not immediately available. Only hours before the hurricane hit, the Goldsborough had returned to port after six months at sea, the spokesman said. Its 20 officers and 320 crewmembers were met at the dock by 150 wives, other family members and friends. There were some reports of injuries on other Navy vessels, but details were sketchy.

Most of the evacuations came in the low-lying areas of Kauai. In Lihue, Kauai's capital city of 4,000 people, a warehouse was flattened and the copper roof blew off the First Hawaiian Bank building.

Some 400 evacuees spent Tuesday night huddled in a neighborhood center in Kilauea, 20 miles north of Lihue, singing "God Bless America" and Christmas carols. "There were lots of butterflies in the building," said Joan Allee, 50, a secretary from Anaheim, Calif. "It was one of the scariest times I've had."

There was no electricity on Kauai except for a little produced by emergency generators. Power failures also plagued Oahu, including parts of Honolulu. Much of the telephone service between Hawaii and the U.S. mainland was out for several hours.

Ariyoshi said he was "not aware of any injuries" to the 226 residents of the privately owned island of Niihau.