Montanans Get Unusual Sight--They See Their Air

HELENA, Mont. — The smog over western Montana valleys today was so unusual that the National Weather Service put out a special advisory explaining to puzzled Montanans what the crud was.

Visibility in Helena was only six miles this morning, virtually opaque by Montana standards. Tuesday afternoon, the visibility was 40 miles.

The weather service explained that the dirty air was “a weather phenomenon usually seen in the industrial Eastern United States.”

“Generally speaking, high humidity, high pressure at the surface and a high concentration of industrial pollutants combine in the populated Eastern United States to produce a milky dirty sky during the day along with reduced visibilities,” the weather service said in an advisory that goes to radio stations and newspapers.