A truck crosses a destroyed bridge on the outskirts of Batal, Pakistan, around 100 kilometers north east of Islamabad

With the harsh Himalayan winter just around the corner, relief workers in Pakistan say providing shelter for millions of survivors of last week's massive earthquake is their top priority. Bad weather is causing fresh delays in relief operations and aid agencies say time is running out.

For the second day running, freezing rain is disrupting aid efforts and soaking thousands of homeless families in the areas hardest hit by the 7.6 magnitude earthquake.

Dorothy Blaine, with the Irish aid agency Concern, says that with winter approaching, providing the victims with proper shelter is critical to their survival.

"We've got four of the worst months of the year for that part of the country; there'll be heavy snowfall [and] massive drops in temperature, which we're already beginning to see following the rainfall," she said.

In Muzaffarabad, capital of Pakistani-controlled Kashmir, near the epicenter of the quake, relief agencies are scrambling to get tents and blankets to as many people as they can.

The Pakistani government is planning to set up enormous tent cities for up to half a million people in affected areas in Kashmir and the neighboring North West Frontier Province.

But more than a week after the earthquake, thousands of survivors have little more than plastic sheeting to keep them dry.

Why is it taking so long to get them help?

Rescue workers say the conditions in Kashmir are some of the most challenging they have ever encountered.

Local supplies of winterized tents ran out days after the quake struck, forcing Pakistan, a world leader in the textile industry, to import supplies.

Traffic jams caused by thousands of volunteers driving into affected areas are also delaying professional relief workers with emergency provisions.

In other places, it is the rugged landscape that is preventing aid from reaching the disaster areas.

Dr. Arif Noor, with the aid agency Mercy Corps, says medical teams have still not reached some remote villages, as access roads remain buried beneath massive landslides.

"Even a week later there are areas about which nobody is certain that this is the extent of damage, and these many people have died and these many people need immediate medical attention, even after a week," he said.

Helicopters have been airlifting food into some isolated communities and evacuating the sick and injured, but the rain has grounded the operation. The Pakistani military also announced that one of its helicopters crashed Saturday night, killing all six crewmembers.

So far, the earthquake has claimed nearly 40,000 lives in Pakistan and over 1,000 in India.