There were thunderstorms in the area of Edgemont at the time of the C-130 air tanker crash Sunday in the Black Hills but it's hard to say whether they were a contributing factor in the crash.
Fifteen minutes before the plane was reported down, there was a report of half-dollar sized hail about 13 miles to the south of Edgemont.
The thunderstorms continued moved to the east and about the time of the crash, the storms had already moved away. However it is very likely on the backside of these storms that you get some downward descending air. That can cause problems with aviation but C-130s are built to fly through hurricanes.
Visibility could have also been a problem. High resolution satellite images show thick, gray smoke in Fall River County Monday afternoon. It's even been found in Central and Eastern South Dakota.