wildfires

Different parts of the country can tailor the guidelines.

Coulson Aviation in the U.S. state of Oregon says one of its Lockheed large air tankers was lost.

Some Republicans are skeptical, saying California should use existing money to address the problem.

Even among wildfire experts, understanding of health impacts from smoke was elusive until recently.

The smoke has drifted into Montana, North Dakota, South Dakota, Washington state and Wyoming.

The smoke will likely persist through the weekend, with a cool front causing some improvement Sunday into Monday.

High pressure will bring in smoke from the wildfires burning in the west.

Yellowstone officials say the park had eight fires this season, six of which were caused by humans and two that were started by lightning.

The website offers up-to-the-minute updates on air quality in Cheyenne, Casper, Laramie, and other locations.

Summer lightning storms dumped less rain than usual and weather conditions kept humidity low.