Watching from afar, I am struck by the high level of the rescue work at Yushu, the Tibetan autonomous prefecture in Qinghai province, western China, which was devastated by a 7.1 magnitude quake on April 14.

With the death toll climbing to 2,064 by Tuesday, the disaster came as a complete surprise to the local people, destroying their homes in moments. To them, the catastrophe is unprecedented.

Also unprecedented is the level of the rescue work, which started almost as soon as the first shock wave was over.

It is unprecedented to carry out rescue work at such a high altitude. While the seat of the prefecture, Gyegu, is at an elevation of 3,700 meters, the average altitude of Yushu is 4,000 meters above sea level. In the hinterland of the Qinghai-Tibet Plateau, the "roof of the world," Yushu is known as "Asia's Water Tower" as three of the continent's major rivers start there, namely the Yangtze, the Yellow and the Lancang or Mekong rivers.

Having been to Yushu several times in its best season, I know how challenging the physical conditions must be for the rescue workers, most of whom have never been that high before. People from lower altitudes run out of breath easily when they go there, even when they are idle. If they move, they must do so slowly. The rescuers, of course, do not have the luxury of acclimating slowly. Also, they must deal with the aftershocks, the striking temperature differences between day and night, the changeable weather, and many other difficulties.

Rescue work is physically exhausting. Already one rescuer has died of altitude sickness. Yet those who rushed to Yushu have braved all these challenges and raced against time to save lives. So far they have rescued more than 10,000 survivors, and transferred more than 1,000 seriously injured to other cities for better medical treatment.