At least tens of thousands of people were evacuated and there were reports of fighting at gas stations as people fuel up their cars to move inland in Hawaii.
"We have been hearing those reports and we've asked everybody to stop doing that, to get out of the way and that their hindering the evacuation," Honolulu Mayor Peter Carlisle said.
"It's not just a wave," Carlisle warned. "It's a series of waves and no one knows which one will be the strongest, no one knows which one will do the most of damage and we don't even know how long they will last, they could last for a series of hours."
Brian Shiro of the Pacific Tsunami Warning Center said the tsunami that was then headed for the West Coast "loses a little bit of power because of friction from the bottom of the ocean, but this tsunami is pretty sufficient."
Shiro said the West Coast could see waves as high as 9 feet.
San Francisco activated its emergency operations response team and closed its coastal highway. All coastal access to San Francisco area beaches were also closed.
Los Angeles was warned that the tsunami would arrive at 8:30 a.m. local time, but that another, bigger wave was expected two hours later when the tide would be rising, a potential threat of serious flooding, the U.S. Geological Survey said.
Warning sirens began blaring in some Oregon coastal communities in the small hours of the morning, and residents were urged to seek higher ground.
Orgeon officials said highways were congested with residents evacuating low lying ares near Florence.
Sam McAlmond, a resident of Gold Beach, Ore., chose not to evacuate, but is prepared to leave his home if it becomes necesary.
"This doesn't happen too often. We liked to see it if and when anything happens," he said of the tsunami. "We have all of our necessary equipment -- fresh water and food. Filled up the tank with gas and there is an escape route."
McAlmond said he had not seen any significant waves from his beach front home.
The Associated Press contributed to this report.