EXPLAINER: How to stage Olympics in a snow-challenged city

BEIJING (AP) — Dry Beijing barely gets any winter precipitation, making this year's Winter Games the first to rely almost entirely on artificial snow. Organizers are touting the event's green credentials, but experts do worry about the environmental impact of such a massive snowmaking operation given the huge amounts of water and electricity it takes.

At Yanqing north of Beijing, where organizers built the alpine ski venue from scratch, the slopes stand out as ribbons of white contrasting starkly against the surrounding brown hillsides. Snowmakers have also been deployed farther north in Zhangjiakou, which is hosting freestyle skiing, ski jumping and biathlon.

All of it is the product of months of snowmaking using sophisticated European equipment.

Here's a closer look at the Olympic snowmaking operation:

HOW IT WORKS

Natural snow is formed high up in the clouds when water vapor molecules cling to tiny particles like pollen or dust. In scientific lingo, these specks are dubbed nucleators. They create a snow nucleus that then attracts more water molecules to form snowflakes.

Snowmaking equipment tries to duplicate this process, artificially, by spraying atomized water into the air along with mechanically created nucleators — tiny ice crystals — that act as seeds for the manufactured snowflakes. This process has been around for decades: simulated snow was first used at the 1980 Olympics in Lake Placid, New York.

SNOW GUNS

TechnoAlpin won the bid to supply the Beijing games with snowmaking equipment, a contract worth $22 million.

The Italian company has blanketed the slopes with 272 snowmaking fan guns and another 82 stick “lances” to produce “technical snow” for the Winter Olympics skiing and snowboarding venues. They're all hooked up to a system of high pressure pumps...