ST. FRANCIS, S.D. - A tornado that tore through St. Francis early Monday morning has been classified as an EF1, according to preliminary damage information released by the National Weather Service (NWS). Six people were injured in the storm.

Survey teams estimate the tornado packed peak winds of 98 miles per hour.

The tornado first touched down two miles southeast of Spring Creek, just south of BIA Route 30, remaining over open fields before destroying a heavily built outbuilding anchored to a cement slab. Contents from the building were thrown about 50 yards up a nearby hill.

NWS says the tornado intensified as it crossed BIA Route 30, destroying a single-wide mobile home. The undercarriage was tossed 100 yards from its foundation, with all walls leveled.

As the tornado moved closer to St. Francis, NWS says it damaged trees and power poles. Near the Catholic church, multiple tree trunks were snapped at the base. It then swept through the west side of town, tearing roofs off the community center and an elderly living facility.

Though it began to weaken slightly after leaving St. Francis and shifting more north-northeast, NWS says the tornado still caused damage in Rosebud. There, it significantly damaged the roof of the water supply center and an adjacent storage facility. Debris was thrown to the west and southwest.

The tornado ultimately dissipated about two miles north of Rosebud.

The NWS emphasized that the information is preliminary and subject to change following a final review.