(Dufur, OR)  --  A large wildfire in northern Oregon is forcing people to evacuate their homes.  Oregon Governor Kate Brown invoked an emergency conflagration act in response to the fire dubbed the South Valley Fire.  More than 170 homes are threatened leaving more than 500 people under evacuation orders in the city of Dufur, just east of Portland.  The fire grew to 15-thousand acres since it sparked Wednesday afternoon.  About 150 fire crews have joined in the battle with more expected to arrive throughout the day.  As of Thursday morning it was five-percent contained.  Investigators say it was caused by a human.