Rosemary L. Powell, 80, of Renton, who suffered critical injuries in a house fire on Talbot Road South Wednesday afternoon in Renton, has died.

The King County Medical Examiner’s Office determined she died of a cervical spine fracture, a broken neck. Her death was ruled an accident.

Details of how she suffered the injury weren’t immediately available.

She was transported to Harborview Medical Center in Seattle, where she died on Thursday. Paramedics had found her unconscious and unresponsive at about 1:30 p.m. at the fire scene in the 3100 block of Talbot Road South.

Fire investigators could not scientifically determine what started the fire, so the cause is listed as undetermined, which is not uncommon, according to Erik Wallgren, deputy fire chief for the Renton Fire and Emergency Services Department.

The fire started outside the house, according to Wallgren.

Renton fire crews also responded to a house fire just after 9 a.m. Thursday in the 16600 block of 105th Avenue South. No one was home at the time, according to Wallgren.

The fire started inside the house. Renton fire investigators determined the fire was accidental.

The fire department will have additional details available about the two fires early next week.

Wallgren again cautioned that the dry weather has dried out brush, grass and other vegetation, creating ideal conditions for an outdoor fire. In such conditions a spark from a lawn mower or a tossed cigarette could start a fire, he said.

“We want to be very cautious,” he said.