Spokane Valley Fire authorities said the Upriver Beacon Fire started as a structure fire and quickly spread to the northeast. Over the course of the evening, the fire was upgraded to a third alarm and Department of Natural Resources was asked to respond along with air support. At the height of the fight Tuesday afternoon, more than 50 support vehicles were assisting in extinguishing the fire. Fire crews are still on scene Wednesday morning as the fire burns on East Upriver just east of Frederick. Officials said fire activity did die down overnight, but hotspots and active flames remain within the perimeter. Crews have set a perimeter around 100 percent of the fire.