A Custer County rancher lost 200 tons of hay to fire Tuesday morning as the remnants continue to burn today and possibly throughout the week. Meanwhile, investigators are trying to determine the cause of the fire that burned the 400 large round bales near Hermosa.

According to Rapid City Fire and Emergency Services Battalion One officials, it is unclear what caused the fire, but it may have been spontaneous combustion of the tightly baled grasses not allowed to dry completely before going through the haying equipment.

A neighboring rancher saw the fire and called emergency crews at about 11 a.m Tuesday to a ranch about 1 mile east of Hermosa on Highway 40. Fire fighters and county workers pulled the bales apart to allow them to burn, being careful to secure the area and not allow embers to start fires in other haystacks in the hay yard.

Fire crews on scene included Hermosa Volunteer Fire Department, Fairburn Volunteer fire Department, Keystone Volunteer Fire Department, Rapid Valley Volunteer Fire Department, Custer County Highway Department and the Rapid City Fire Department.