Investigators confirmed the location where the Upriver Fire sparked was in a vacant home. Despite pinpointing the location where the fire started, investigators were not able to determine a cause.
Due to the extent of the damage to the house, firefighters were not able to trace what first ignited the fire. The homeowner told investigators the home had been vacant for decades, though it was maintained and electricity was still connected.
Investigators say, while they weren't able to confirm a cause, their hypothesis is a potential break-in and electrical failure. The Upriver Fire sparked in June 2026, destroying more than a dozen homes.