The most powerful earthquake to hit Nepal in more than eight decades roared across the impoverished mountain kingdom just before noon Saturday, killing more than 1,800 people, some as far away as India and Bangladesh, and devastating a crowded base camp at Mt. Everest.
Signature buildings collapsed in the ancient Old Katmandu quarter of the capital, including the Dharahara Tower, a 200-foot-tall structure built in 1832. Emergency response officials said at least 60 tourists were buried under rubble while visiting the popular site at the busiest time of day. Other historic buildings in Katmandu Valley's UNESCO-designated heritage sites were also damaged or destroyed by the magnitude 7.8 temblor, including Patan Durbar Square.
"Responders are trying to dig people out," said Prajana W. Pradham of the CARE relief agency. "This quake was so big."
Officials said the death toll was likely to increase dramatically, perhaps to as many as 10,000, as emergency response crews reach more remote areas of the country of 28 million.
On Saturday evening, Katmandu, a city of 1 million, was turned into a teeming tent community where survivors dragged their mattresses to sleep outdoors, fearful that dozens of aftershocks would bring down damaged homes and bury them.
"We don't want to go home now with so many aftershocks through the day, and even just now it is too risky to stay indoors," said Sakila Gurng, a resident of the densely populated New Baneshwor neighborhood who was camping at a school.
A light rain fell in the early hours Sunday, adding to the discomfort of the hordes of displaced Katmandu residents but appearing to have little immediate effect on relief operations, which were complicated by the widespread rubble.
Television and Internet services were disrupted and phone and electricity lines were down.
The quake struck at the height of the Himalayan climbing season, when foreign visitors flock to the capital and the world's tallest mountain. Among the dead was a Bay Area technology engineer, Dan Fredinburg, one of at least 17 people killed when an avalanche set off by the earthquake swept into the main base camp for climbers attempting to reach Everest's 29,035-foot summit.
A toll of 1,805 confirmed dead provided by Home Ministry official Laxmi Dhakal to news agencies in Katmandu referred only to Nepalese victims. The ministry said 4,718 people had been injured. The known fatality count across the subcontinent was at least 1,874, including at least 60 reported deaths in India, four in Bangladesh and five in China's Tibet region.
The U.S. Geological Survey said its models indicated that damage could amount to as much as half of Nepal's gross domestic product, one of the lowest per capita in the world.
Within hours, aid began pouring in, as soon as Nepal's sole international airport reopened after a closure prompted by communications outages and concern that the runway might have been damaged.
Nepal Republic Media, a private news outlet in the country, said an Indian air force C-130 plane carrying 40 rescue and medical personnel had arrived in Katmandu along with 3 tons of supplies. Three other aircraft were also being sent from India, Indian Foreign Secretary Sujatha Singh said on Indian television. One was carrying a mobile hospital.
Washington was sending a disaster assistance response team to Katmandu and the U.S. Embassy was immediately releasing $1 million in initial humanitarian assistance, National Security Council spokeswoman Bernadette Meehan said.
The Nepalese government announced that all foreign relief personnel would be issued free visas upon arrival in the country.
Nongovernment organizations issued urgent appeals for money and volunteers to help treat the thousands injured in the disaster, which also had rendered many of the country's medical facilities inoperable and probably contaminated Katmandu's water system.
"Bandages, antiseptic creams, alcohol pads, antibacterial hand sanitizer, plastic bags, sanitary napkins and water-purification tablets. It is vital that we deliver these items as quickly as possible!" said an appeal from NFCC International.
Katmandu was a panorama of destruction, with toppled utility poles, collapsed walls, churned-up asphalt and debris from crushed houses sprawled across the landscape.
Many structures in Nepal are made of unreinforced brick or crushed stone, and scores of people were injured in the quake by sharp objects sent flying from collapsing buildings. Clouds of dust swirled around the panicked exodus as walls were shaken into rubble by the quake.
The aftershocks that sent almost the entire population of the capital out of doors also prompted evacuation of its hospitals. Patients in pajamas could be seen sitting on mattresses that had been carried out to parking lots, along with intravenous drips to which many were tethered.
Katmandu was in "near total darkness" by 9:30 p.m., said Kunda Dixit, editor of the Nepali Times.
Fallen walls blocked some of the capital's narrow streets, further hampering the overwhelmed emergency crews, said Santosh Sharma, an emergency response coordinator with CARE. He said he rushed to help two people trapped in rubble at a nearby home.
"Their house is completely collapsed," Sharma said. "They had bad wounds and were bleeding. We took them to the nearest health center where they got first aid."
Pramod Bhagat said he set up a sleeping area outside his home where he spent the night with cookies, iced tea and a Kindle to take his mind off the tragedy. He said he wore a bike helmet all night to protect himself from debris that continued to fly around from aftershocks.
Katmandu was quiet by midnight, save for the sound of barking dogs and the occasional chants of "Ayo! Ayo!" ("It's come! It's come!") as neighbors shouted to one another at the onset of each aftershock, said Rupa Joshi, communications specialist for UNICEF in Nepal.
Joshi said she took to the streets after the earthquake, trying to calm traumatized families and to survey the damage.
"Not sure how many can sleep with so many aftershocks," she told The Times. "Many people are outdoors, in the streets and the open grounds."
At nightfall in Thamel, a tourist district of the capital popular with counterculture travelers since the hippie movement of the 1960s, backpackers could be seen walking in droves in search of a place to pitch their tents for the night.
A picture provided from the Everest base camp by Azim Afif, leader of a Malaysian climbing team on the mountain, showed the eerie scene of crushed tents and debris strewn across a moonlit slope of the mountain range known as "the roof of the world."
The quake was centered 48 miles northwest of Katmandu. It was most strongly felt in the capital as well as the densely populated Katmandu Valley, but it also shook several cities across northern India, and was felt as far away as Lahore in Pakistan, Lhasa in Tibet and Dhaka in Bangladesh.
Officials said the quake occurred at a depth of only seven miles, which is considered shallow in geological terms. The shallower the quake the more destructive power it carries, and witnesses said the trembling and swaying of the earth went on for several minutes.
A magnitude 6.6 aftershock hit about an hour later, and at least 20 other aftershocks followed the huge temblor.
The quake was the same magnitude as the one that devastated San Francisco in 1906.
In January 1934, an 8.2 quake rumbled across Nepal, killing an estimated 10,000 people there and more than 7,000 in India. Large swaths of Katmandu were destroyed.
Though the extent of the damage and the scale of the current disaster are yet to be ascertained, the quake will probably put a huge strain on the resources of this poor country, which is best known for Everest. The economy of Nepal is heavily dependent on tourism, principally trekking and Himalayan mountain climbing.
The quake-induced avalanche that struck the base camp followed by just more than a year a disastrous avalanche in which 16 Sherpa guides died.
Javier Camacho Gimenez, a mountaineer and photographer who was at the Everest base camp, said avalanches had buried tents, including those of Chinese and Japanese climbers.
Nepalese tourism officials said 10 bodies had been recovered from the avalanche area. The ekantipur website said there were at least 1,200 people on the Everest climbing routes, including cooks, porters and guides for the predominantly foreign climbers.
"The situation in the Everest base camp is now chaos," Camacho told the Spanish news agency EFE. "Helicopters cannot access the area due to bad weather."
Alex Gavan, a mountaineer, tweeted that the quake triggered a massive avalanche from Pumori, about five miles west of Everest.
"Huge disaster," he wrote. "Helped searched and rescued victims through huge debris area. Many dead. Much more badly injured. More to die if not heli asap."