The Philippines is annually buffeted by tropical storms and typhoons, which are called hurricanes and cyclones elsewhere. The nation is in the northwestern Pacific, right in the path of the world's No. 1 typhoon generator, according to meteorologists. The archipelago's exposed eastern seaboard often bears the brunt.
Even by the standards of the Philippines, however, Haiyan is a catastrophe of epic proportions and has shocked the impoverished and densely populated nation of 96 million people. Its winds were among the strongest ever recorded, and it appears to have killed many more people than the previous deadliest Philippine storm, Thelma, in which about 5,100 people died in the central Philippines in 1991.
The country's deadliest disaster on record was the 1976 magnitude-7.9 earthquake that triggered a tsunami in the Moro Gulf in the southern Philippines, killing 5,791 people.
Defense Secretary Voltaire Gazmin said Aquino was "speechless" when he told him of the devastation in Tacloban.
"I told him all systems are down," Gazmin said. "There is no power, no water, nothing. People are desperate. They're looting."
Tacloban, in the east-central Philippines, is near the Red Beach on Leyte Island where U.S. Gen. Douglas MacArthur waded ashore in 1944 during World War II and fulfilled his famous pledge: "I shall return."
It was the first city liberated from the Japanese by U.S. and Filipino forces and served as the Philippines' temporary capital for several months. It is also the hometown of former Filipino first lady Imelda Marcos, whose nephew, Alfred Romualdez, is the city's mayor.
One Tacloban resident said he and others took refuge inside a Jeep, but the vehicle was picked up by a surging wall of water.
"The water was as high as a coconut tree," said 44-year-old Sandy Torotoro, a bicycle taxi driver who lives near the airport with his wife and 8-year-old daughter. "I got out of the Jeep and I was swept away by the rampaging water with logs, trees and our house, which was ripped off from its mooring.
"When we were being swept by the water, many people were floating and raising their hands and yelling for help. But what can we do? We also needed to be helped," Torotoro said.
In Torotoro's village, bodies were strewn along the muddy main road as now-homeless residents huddled with the few possessions they managed to save. The road was lined with toppled trees.
UNICEF estimated that 1.7 million children live in areas affected by the typhoon, according to the agency's representative in the Philippines, Tomoo Hozumi. UNICEF's supply division in Copenhagen was loading 60 metric tons of relief supplies for an emergency airlift expected to arrive in the Philippines on Tuesday.
"The devastation is ... I don't have the words for it," Interior Secretary Mar Roxas said. "It's really horrific. It's a great human tragedy."