One of the most powerful earthquakes in modern history shook Russia’s remote east coast Wednesday, sending tsunami waves hurtling across the Pacific Ocean and putting nations from Japan to the United States to Chile on high alert with millions urged to evacuate.

The U.S. Tsunami Warning System (tsunami.gov) will be updating its guidance as experts learn more about the threat, including maps showing what areas face what risks. In the minutes and hours after a major earthquake,

Hawaii officials say the timing of the tsunami warning and evacuation orders following this week's massive earthquake off Russia helped make for severe traffic congestion in some areas