Canadian authorities upped the Alberta flood death toll to four Wednesday, after an autopsy revealed an 83-year-old woman had drowned in her ground-level apartment near the Elbow River.

Police said they had asked her in person last week to evacuate and believed she would comply, but for unexplained reasons she did not flee the flood zone along with nearly 100,000 others who were displaced in the disaster.

Three bodies were also found Saturday in the town of High River, after heavy rains caused Alberta rivers to overflow.