An apartment fire killed a 94-year-old woman in western Minnesota, authorities said Sunday.

The blaze broke out about 3:15 p.m. Saturday in an A residence in Granite Ridge Place in the 500 block of Skyview Drive in Granite Falls, according to the Yellow Medicine County Sheriff’s Office.

The flames were extinguished within 20 minutes, and emergency responders located the body of Vivian Jeseritz.

Alerted by an automated smoke alarm were fire, ambulance and police personnel. Firefighters saw smoke coming from above the apartment door, entered and encountered more smoke and flames, the Sheriff’s Office said.

Investigators have yet to say how the fire started.