Oregon's largest wildfire in more than a century threatened power lines feeding several Northern California towns yesterday as crews tried to stop a slow creep along its southeastern flank. Hand crews had created three or four fire lines in front of the advancing flames west of O'Brien, but said they would have to ask Pacific Power to shut down the power lines if the wildfire got too close. When carbon-rich smoke thickens around the cables, it can cause the electricity from the lines to arc, endangering firefighters. Turning off the power would put the California towns of Gasquet, Hiouchi and...