Santa Rosa Fire officials are blaming a tree branch falling onto power lines on King Street for a power outage. The outage began just after 8:30 last night and affected nearly 18-hundred homes and businesses in downtown Santa Rosa and near the SRJC neighborhood. The outage affected businesses on Mendocino Avenue and homes from near College Avenue and Slater Street in the west to Spencer Avenue and North Street in the east. Power to all customers was restored less than an hour later.