SALT LAKE CITY (AP)--Haze obscures the snowy mountains that watch over this city, submerging the valley in a choking smog that causes burning eyes and tightness in the chest.

The air hanging over Salt Lake City this week -- hardly the stuff of Olympic postcards -- may leave many visitors talking more about the thick, gray air than Utah's Alpine beauty.

"Everything they're here to see won't be seen," local contractor Larry Donelson said.

Welcome to Salt Lake City's dirty little secret, a weather phenomenon called an inversion that can trap pollutants in the valley for days, or sometimes weeks, at a time.

When it's really bad, parents are warned to keep their children inside.

"It's nasty living down here. Everyone has colds. Everything's dirty," said Donelson, who has lived here for 27 years. "It gets so bad you can't see half a block away. And I have a dry, itchy, sore throat all winter."

The latest inversion settled over the city on Monday, just in time to welcome Olympians and visitors who arrived early.

Mother nature could blow the dirty air out of the area, but only with a snowstorm, and that could cause havoc with preparations for the Games. Forecasters say a storm could come on Friday, just in time for the opening ceremony.

Larry Dunn, a meteorologist at the National Weather Service in Salt Lake City, said a storm should drop up to 2 inches of snow on the valley on Friday.

But Dunn said the storm could veer north to Idaho or fizzle before getting here, leaving one option for escaping the haze.

"If you want to get out of it you drive to the mountains," said Tom Potter, the Salt Lake Organizing Committee's weather coordinator.

An inversion is a weather condition that traps a cold layer of smog under a warmer layer of air. Pollution from vehicles and factories gets stuck in the valley, instead of floating away, as it does in the summer.

The increased number of buses and cars in the area for the Olympics could make it even worse.

Healthy people don't usually have much trouble with the smog, other than a little wheezing. But young children, the elderly and people with chronic cardiovascular problems face a higher risk of developing more serious conditions, said Dagmar Vitek, deputy director of medical services for the Salt Lake Valley Health Department.

"It would start with burning eyes, burning throat, a cough," she said. "They can develop more infectious diseases like bronchitis or pneumonia."

"The athletes are healthy people so they shouldn't be affected by this," she added.