Tsunami waves have begun surging ashore on Hawaii's Big Island, more than 15 hours after being triggered by an 8.8-magnitude earthquake off the coast of Chile.
The Pacific Tsunami Warning Center confirmed the tsunami reached Hawaii just after 11:30 a.m. local time, 4:30 p.m. ET.
Initial reports indicate the waves have been smaller than expected, but officials are warning residents to remain on high alert. The tsunami is a series of waves that will continue to march toward Hawaii's shores.
"This could be bigger but we don't know yet," said Nathan Becker of the PTWC, noting the first wave measured 1 meter, or roughly 3 feet. Later waves could be larger, he said.
"Clearly, a tsunami is taking place now," Becker said.
The waves will now continue moving north towards the other Hawaiian Islands and onward into the Pacific.
"The time from one tsunami wave to the next can be five minutes to an hour," a Pacific Tsunami Warning Center (PTWC) bulletin reads. "The threat can continue for many hours as multiple waves arrive."
Residents are advised to remain on high ground until local authorities give the "all clear," which could come no sooner than two hours after the estimated time of the tsunami's arrival.
The state had significant lead time in preparing for the tsunami, sounding alarms to evacuate coastal areas starting at 6 a.m. local time. It was the state's first widespread evacuation in 16 years.
Hawaii Gov. Linda Lingle said she believes the state was "well prepared."
The PTWC issued a tsunami warning -- its highest alert -- early this morning, warning of damage along the shores of all islands in the state.
An estimated 40,000 to 50,000 people were told to evacuate flood-prone areas of the Big Island. The streets of downtown Hilo were empty and police cordoned off an area a quarter-mile from the shore.
Emergency workers went door to door, urging people to heed the sirens, and homeless people who live on the beaches were transported away in buses.
Crowds of people gathered at high vantage points, on rooftops and along roadways, to safely watch the waves approach.
Elsewhere, roadblocks have been set up to prevent beach access, and along Waikiki, one of Hawaii's most famous beaches on Oahu, the sands were deserted.
The Federal Aviation Administration closed Hilo International Airport on the low-lying eastern side of Hawaii's Big Island. Honolulu International Airport on Oahu is expected to remain open.
As a precautionary measure, the U.S. Navy ordered four ships to leave the port of Pearl Harbor and remain at sea, where they will escape the crush of incoming water that could thrust them against the shore.
The National Weather Service had reported that waves at Marquesas Island on the northern edge of French Polynesia, hundreds of miles south of Hawaii, were smaller than forecast, saying in a tweet "Hawaii impact could be less than initial expectations."
Immediately following the 8.8-magnitude quake off central Chile, 4- to 8-foot waves were reported along the South American coastline.> The president made a statement outside the White House this afternoon, offering his condolences to victims of the Chile quake and assurances that the administration is making preparations for the tsunami.
"We can't control nature, but we can and must be prepared for a disaster if and when it strikes," Obama said.
The Federal Emergency Management Agency says it has "pre-deployed assets" in Hawaii, including food, water, generators and other resources ready to roll out as needed.
In addition to Hawaii, the tsunami warning also affects Guam, American Samoa and coastal areas of California and Alaska. The PTWC forecasts waves of 2 to 3 feet to could surge on the California beaches of La Jolla, Santa Monica, Los Angeles and Morro Bay.
Following a 9.5-magnitude quake that struck Chile in 1960, the ensuing tsunami killed more than 200 people, including 61 in Hawaii.
ABC News' Arash Ghadishah, David Herndon and Luis Martinez contributed to this report along with The Associated Press and ABC affiliate KITV in Honolulu, Hawaii.
Source is wondering what's up in Hilo.