Fire spokesman Dave Wells says the fire made a run along the river Wednesday evening. He says as smoke cleared, flames from the fire were visible from The Dalles, a city of about 14,000 that is about 6 miles from the blaze.
Wells says an unknown number of residents in an outlying Dalles neighborhood were told to be ready to leave if necessary.
So far no homes have burned. Wells said firefighters planned to work through the night protecting residences.
Fire spokesman Justin de Ruyter says five helicopters dropped water on the blaze earlier as winds gusted to more than 30 mph.
A section of U.S. Highway 30 was closed in the area. Rowena is about 75 miles east of Portland.
The fire began in brush Tuesday night and quickly spread to about 200 acres of timber and scrub oak in rocky, steep terrain. It grew on Wednesday but no updated acreage figure was available pending an infrared flight scheduled overnight.