UPDATE 6:30 a.m. -  According to Rocky Mountain Power, the power outage is affecting more than 8,400 of its customers.  The utility is estimating it might take until 5:30 p.m. to restore electricity.

Many Casper residents are starting their Sunday without electricity. Shortly after 5:00 a.m., Casper Fire officials say a transformer station in the Bonnie Brae area failed, cutting power to an unknown number of homes and businesses.

The failure was accompanied by a bright flash and sparks. Fire officials say electrical smells and mild smoke can be expected over a wide portion of the city.

Video submitted by Josh B.