An explosion in a power transformer startled residents of the Ponderosa Cascade neighborhood east of Sisters early Saturday evening. Several people heard the explosion and then saw flames spreading to nearby brush.  Our news partner, News Channel 21 reports neighbors worked together using garden hoses to slow the fire until firefighters arrived. Central Electric Co-Op officials say one of their transformers exploded and sparked the fire. The lights in the area flickered, but came right back on. There were no injuries and no damage to structures.