ISLAMABAD, Pakistan – Three months after South Asia’s monster earthquake, hundreds of thousands of survivors face a fight to survive the Himalayan winter, huddling in unheated tents and tin shacks near the ruins of their homes.

Health workers expect fatalities from cold-related diseases like pneumonia – anecdotal reports suggest dozens of children already have died – but Pakistani officials say enough shelter and supplies are in place to prevent a “second wave” of deaths on top of the 87,000 killed by the Oct. 8 temblor.

Senior U.N. aid officials are more circumspect, saying nobody can predict the weather’s impact. But they are backing away from dire warnings in the immediate aftermath of the disaster when the world body’s humanitarian chief Jan Egeland said tens of thousands more could die without more aid.

Jan Vandemoortele, the U.N. humanitarian coordinator for Pakistan, said there was now the capacity – dozens of helicopters, scores of clinics and thousands of tons of food stocks – to keep people alive through the crisis, so long as the weather periodically cleared to let aid delivery and medics reach the vulnerable.

“On that basis, we will be able to prevent a second wave (of deaths),” he said.

A mild December allowed more time than expected to rush in aid for more than 3 million left homeless by the magnitude 7.6 quake that reached across a 12,000-square-mile swath of mountains, stretching from northwestern Pakistan eastward into India’s portion of disputed Kashmir, where 1,350 people also died in the quake.

The new year started badly. For three days, driving rains tore through the valleys and up to 4 feet of snow fell on mountain villages, where temperatures dipped to 5 degrees.

“This weather is the nightmare we were expecting,” said Larry Hollingworth, the U.N. deputy humanitarian coordinator. “People are now at their most vulnerable.”

Helicopters were grounded and roads were blocked, virtually halting relief efforts for several days. On mountainsides, hundreds of flimsy tents collapsed under the weight of snow. In the relatively well-supplied lowland camps that house about 250,000 displaced people, rain brought floods that drenched tents.

“We are used to the winter because we live in the mountains, but here we have no proper shelter. The children are getting sick,” said Akber Jan, a quake widow who lives with her seven children in a tent at a muddy camp in Muzaffarabad, the capital of Pakistan’s portion of Kashmir.

Survivors on mountaintops were spared the rain, but little else.

At Maidan village, 6,930 feet up in the remote Allai valley, the snow is now knee-deep, and residents were starting Friday to slaughter their valuable livestock to supplement food handouts from the U.N. World Food Program.

“We only used to plant maize, and there’s not much left. We have yogurt, but we are dependent on WFP for other food,” said Saleem Khan, a 32-year-old village elder.

The U.N. estimates that across the quake zone, 400,000 people have opted to stay in villages above 5,000 feet, where the Pakistan army is helping to erect tens of thousands of corrugated iron shelters. At lower elevations, about 1.9 million are living in tents.

Pakistan’s federal relief commissioner, Maj. Gen. Farooq Ahmad, was confident that adequate shelter has been provided to prevent major loss of life.

“The risk (of more deaths) would have been there if we had failed to provide this,” he said. “People should be reasonably comfortable.”

Nongovernment aid groups are less optimistic, saying the quality of preparation for the winter varies widely from well-supplied camps near urban centers to spontaneous settlements that wait for handouts from aid trucks and choppers.

“There are tens of thousands of people without adequate protection,” said Shaheen Chughtai, a spokesman for Oxfam. “We are poised to see a second wave of deaths unless there’s rapid action. For some people, it may already be too late.”

Vandemoortele said that because of a global shortage, few of the hundreds of thousands of tents are fully equipped for winter. He said what people need now is more warm clothes and quilts.