A trip to the snow-laden Changu Lake turned into a nightmare for more than 3, 500 tourists including hundreds of children on Friday. They were trapped in snowstorm conditions with the temperature dipping to minus 15 degrees at a killing altitude of 13,300 feet before the army pulled them to safety.

The majority of those trapped were from Bengal. Hundreds fell ill, shivering in the icy cold as their vehicles remained stranded near Changu and Baba Mandir for hours. Clad in just jackets and scarves, the holidayers were hardly prepared, mentally or physically, to encounter a blizzard.

The army rescued them and took them to military camps, where warm soup and loads of blankets helped revive most of them. Many had to be admitted to the army medical units for treatment.

In the morning, there was little indication of what was to come. Tourists flocked to the Changu Lake by the hundreds as they do every day. With winter setting in, there was the added attraction of seeing the lake under glittering snow-covered peaks. The tourists got more than what they had asked for.

It started with a heavy shower. The temperature plummeted sharply. The skies seemed to turn clear for a moment but suddenly, heavy snowfall started near the India-China border, 35 km from Gangtok. Roads went under a couple of feet of snow in no time. Over 450 vehicles were immediately trapped.

Local guides assured them that the weather would clear up, but it only got worse. More snow fell. More vehicles got stranded in the higher reaches. What compounded the torture was wind chill. With the mercury dropping to minus 10 and continuing southward, the wind picked up, cutting into exposed skin, finding its way past windscreens, locked car doors and inside jackets.

The administration sent an SOS to the army that has several camps in the area. Unit 17 of the army's elite mountain division swung into action. Aided by the Indo-Tibetan Border Police, Border Roads Organization and local police, they rescued around 1,500 tourists from 230 vehicles. Many had to be rushed for treatment while the rest were given shelter in the army camps.

The remaining tourists were rescued late in the afternoon even though their vehicles remained stranded. Although no casualty has been reported, many are said to be seriously ill. With the weather showing no signs of letting up, Changu Lake could remain out of bounds for tourists this week.