A magnitude 7.7 earthquake has struck off the west coast of Canada, but there were no reports of major damage.
The US Geological Survey said the powerful quake hit the Queen Charlotte Islands at a depth of about 3 miles and was centred 96 miles south of Masset, British Columbia. It was felt across a wide area in British Columbia, both on its Pacific islands and on the mainland.
"It looks like the damage and the risk are at a very low level," said Shirley Bond, British Columbia's minister responsible for emergency management said. "We're certainly grateful."
The National Weather Service issued a tsunami warning for coastal areas of British Columbia, southern Alaska and Hawaii, but later cancelled it for the first two and downgraded it to an advisory for Hawaii.
Gerard Fryer, a senior geologist with the Pacific Tsunami Warning Center, said the first waves hitting shore in Hawaii are smaller than expected.
Dennis Sinnott of the Canadian Institute of Ocean Science said a 27 inch wave was recorded off Langara Island on the north-east tip of Haida Gwaii, formerly called the Queen Charlotte Islands. The islands are home to about 5,000 people, many of them members of the Haida aboriginal group. Another 21 inch wave hit Winter Harbour on the north-east coast of Vancouver Island.
Officials in Hawaii later cancelled the tsunami advisory for the state's coastline, paving the way for beaches and harbours to reopen. The Pacific Tsunami Warning Centre lifted its tsunami advisory three hours after downgrading from a warning and less than six hours after the waves first hit the islands.
The biggest waves - about five feet high - appeared to hit Maui. A popular triathlon set for the island was expected to go on as planned, with an ocean swim. There are no immediate reports of damage, though one person died in a fatal crash near a road that was closed because of the threat.