PARKS, Ariz. (AP) — Thick smoke from a fire set to reduce wildfire risks blinded motorists Wednesday on the main highway across northern Arizona near the Grand Canyon, causing numerous accidents as haze clouded the freeway for hours and reduced visibility to 20 feet, officials said. The fire to burn dry brush and trees was set Tuesday in the Kaibab National Forest that surrounds Flagstaff and officials knew that a wind shift overnight would send smoke toward Interstate 40. But they were surprised that it did not dissipate as predicted, said Brady Smith, a U.S.