Widespread evacuations were under way Tuesday night along the western coast of South America after an 8.2-magnitude earthquake off Chile generated a potentially destructive tsunami — which forecasters said could reach as far as Hawaii.
The Pacific Tsunami Warning Center, part of the U.S. National Oceanic and Atmospheric Administration, issued an "expanding tsunami warning" along the coasts of Chile and Peru. A tsunami warning for Ecuador was canceled, as were tsunami watches in a much broader area encompassing Colombia, Panama, Costa Rica, Nicaragua and El Salvador.
The tsunami center said a wave of nearly 7 feet had been reported off the northern Chilean port city of Iquique, near the epicenter. A wave of about 6½ feet was reported at Pasagua, along with a 6-foot wave at Arica, it said.
The tsunami "may have been destructive along coasts near the earthquake epicenter and could also be a threat to more distant coasts," the agency said, because an "expanding" warning is one that takes into account the possibility that waves could spread rapidly in the opposite direction as wave events unfold.
The National Tsunami Warning Center said there was no threat of related waves along the Alaska, California, Oregon or Washington coasts. But the threat to Hawaii remained under close evaluation.
No alerts were issued, but in an advisory to Hawaii Civil Defense officials, the Pacific tsunami center said some waves could reach the coast by 3:24 a.m. (9:24 a.m. ET).
"No action is required at this time," it said. But "there is a possibility that Hawaii could be elevated to a watch or warning status."
Besides being the beginning of Tsunami Awareness Month in Hawaii, Tuesday is also the 68th anniversary of an enormous wave that killed 159 people in pre-statehood Hawaii — the result of an 8.6-magnitude earthquake near Unimak Pass, Alaska. The tsunami caused significant damage along the West Coast and flooded coastlines all the way south to Antarctica.
Closer to the epicenter, Chilean authorities ordered a full evacuation for coastal regions.
Crews were bracing for a second and even a third possible wave, Chilean Interior Subsecretary Mahmud Aleuy said Tuesday night.
The waves reported off Chile were relatively minor — tsunami waves that devastated Japan after earthquakes in 2011 reached as high as 130 feet — but Aluey said the country would be on tsunami alert for at least six more hours.
"All of the coastal regions need to evacuate," he said. "All I ask is that the coastal region evacuates and does not come back until we say it's OK to do so."
Rick Allmendinger, an earthquake specialist at Cornell University who is monitoring the tsunami in real time, said that "right now the tsunami situation [for Chile] doesn't look grave." But he told NBC News: "Very often, the biggest waves could come later."
Alan Boyle, Julmary Zambrano and Edgar Zuniga Jr. of NBC News contributed to this report.