A lot of farmers are putting up hay in this hot weather, and some caught fire at a dairy farm in Woodbury County Tuesday night.
Authorities call it "spontaneous combustion."
Shortly before 7:00pm firefighters were called to 2634 Dallas Avenue between Luton and Salix, Iowa. It's the home of Sioux Jerseys LLP.
A huge plume of smoke could be seen from Interstate 29 as crews from five departments worked to put out several large bales of hay.
Authorities say someone noticed fresh cut hay starting to smoke, and used a loader to break it up. Doug Boetger, Assistant Chief Deputy Woodbury County, "It has two big, large hay storage facilities. One of the hay storage facilities caught fire and spread rapidly."
Flames started to spread towards the elevator and grainery, but were contained.