Authorities say a 64-year-old woman died of an apparent heart attack during a wildfire evacuation south of Chadron in northwest Nebraska.

The Dawes County attorney’s office says Ronni Davis died Wednesday night. Officials say a neighbor discovered Davis having difficulty breathing while checking on her during the evacuation. Emergency crews took her to a hospital, where she died.

The wildfire is one of two raging in Dawes County. The other is burning between Harrison and Crawford.

Authorities have evacuated about 150 residents. Chadron State College and the local school district canceled classes on Thursday and Friday.

Both fires were started by lightning from a Tuesday afternoon thunderstorm.