Tsunami waves hit Hawaii in the early morning hours Friday and were sweeping through the island chain after an earthquake in Japan sparked evacuations throughout the Pacific and as far as the U.S. western coast.

The Pacific Tsunami Warning Center said Kauai was the first island hit early Friday by the tsunami. Water rushed ashore in Honolulu, swamping the beach in Waikiki and surging over the break wall in the world-famous resort but stopping short of the area’s high-rise hotels.

Waves at least 3 feet high were recorded on Oahu and Kauai, and officials warned that the waves would continue and could become larger.

Roadways and beaches were empty as the tsunami struck the state, which had hours to prepare.

Residents in coastal areas of Hawaii were sent to refuge areas at community centers and schools, while tourists in Waikiki were moved to higher floors of their high-rise hotels. People waited in long lines, stocking up on gas, bottled water, canned food and generators, and officials told residents to stock up on water and fill their cars with gas.

“We will have everyone evacuated safely as long as no one panics and people don’t overreact,” Maui County Mayor Alan Arakawa said.

NPR’s Richard Harris has been monitoring reports from wave-sensing buoys in the Pacific Ocean. “The waves are 1 to 3 feet in height, which don’t sound like much, but if they hit the coast, they can amplify tremendously,” he said.

“It’s not a wave like a breaker on the beach — it is actually a surge that can last for five or 15 minutes,” Harris noted.

President Obama directed the Federal Emergency Management Agency to be prepared to assist Hawaii or any western state affected by the tsunami.

The tsunami, spawned by a magnitude 8.9 earthquake off Japan, slammed the eastern coast of Japan, sweeping away boats, cars, homes and people as widespread fires burned out of control. It raced across the Pacific at 500 mph, as fast as a jetliner, and likely won’t change speed until it hits a large area of land, said Kanoa Koyanagi, a geophysicist for the Pacific Tsunami Warning Center.

Waves are predicted to hit the U.S. West Coast between 8 a.m. and 8:30 a.m. PST (11 a.m. and 11:30 a.m. EST) Friday. People near the beach and in low-lying coastal areas of Point Conception in Santa Barbara County were told to move immediately inland to higher ground.

While the tsunami is likely to go around smaller islands, the size of Hawaii’s islands will amplify the waves, which will crash hardest against harbors and inlets.

“They’re going to be coming in with high currents, they can pick up boulders from the sea floor … they can pick up cars, they can pick up fuel tanks, those things become battering rams and so it just amplifies the destruction in a big tsunami,” said Chip McCreery, director for the Pacific Tsunami Warning Center.

Waves almost 5 feet high hit Midway, a tiny island in the North Pacific about 1,300 miles northwest of Honolulu.

“We’re preparing for the worst and we’re praying for the best,” said John Cummings III, spokesman for the Honolulu Department of Emergency Management.

The Honolulu International Airport remained open but seven or eight jets bound for Hawaii have turned around, including some originating from Japan, the state Department of Transportation said.

All harbors are closed and vessels were being ordered to leave the harbor.

The warnings issued by the Hawaii-based Pacific Tsunami Warning Center cover an area stretching the entire western coast of the United States and Canada from the Mexican border to Chignik Bay in Alaska.

In Alaska, a dozen small communities along the Aleutian Island chain were on alert. A wave just over 5 feet hit one area, and there were no reports of damage.

In Oregon, sirens blasted and at least one hotel was evacuated in Seaside in the northe.

The warning was issued Friday at 3:31 a.m. EST. Sirens were sounded about 30 minutes later in Honolulu alerting people in coastal areas to evacuate. About 70 percent of Hawaii’s 1.4 million population resides in Honolulu, and as many as 100,000 tourists are in the city on any given day.

Honolulu’s Department of Emergency Management has created refuge areas at community centers and schools, and authorities on Kauai island have opened 11 schools to serve as shelters for those who have left tsunami inundation zones.

Streets cleared out across Hawaii with usually bustling Waikiki mostly free of any foot traffic, with police ordering every one into the hotels. At the hotels, visitors were evacuated to the third floor and higher.

“The situation we’re confronting right now is unpredictable. We do not know how many waves are going to be coming,” said Honolulu Mayor Peter Carlisle. “We do not know which wave, if any wave, causes the most damage and how long the series of waves can last. As a result of that, it is our responsibility to do those things which are absolutely essential to ensure that human life is saved.”

A small 4.5-magnitude earthquake struck the Big Island just before 5 a.m. EST, but there were no reports of damages and the quakes weren’t likely related, a geophysicist with the United States Geological Survey said.

U.S. Coast Guard rescue crews were making preparations throughout the Hawaiian Islands to provide post-tsunami support, with cutter and aircraft crews positioning themselves to conduct response and survey missions.

It was the second time in a little over a year that Hawaii and the U.S. West coast faced the threat of a massive tsunami. A magnitude-8.8 earthquake in Chile spawned warnings on Feb. 27, 2010, but the waves were much smaller than predicted and almost no damage was reported.

Scientists acknowledged they overstated the threat but defended their actions, saying they took the proper steps and learned the lessons of the 2004 Indonesian tsunami that killed thousands of people who didn’t get enough warning.

The worst big wave to strike the U.S. was a 1946 tsunami caused by a magnitude of 8.1 earthquake near Unimak Islands, Alaska, that killed 165 people, mostly in Hawaii. In 1960, a magnitude 9.5 earthquake in southern Chile caused a tsunami that killed at least 1,716 people, including 61 people in Hilo. It also destroyed most of that city’s downtown. On the U.S. mainland, a 1964 tsunami from a 9.2 magnitude earthquake in Prince William Sound, Alaska, struck Washington State, Oregon and California. It killed 128 people, including 11 in Crescent City, Calif.
Copyright 2011 National Public Radio.