TAMPA, Fla. - Rolling blackouts may occur as early as tonight as Hurricane Irma's high winds move into the Tampa Bay area, Tampa Electric CEO Gordon Gillette said.

The blackouts, which are expected to last 15 minutes at a time, could be expanded if flooding and high winds force power plants to shut down, Gillette said.

TECO has purchased power from other utilities and may curtail power from large "interruptible" customers in mandatory evacuation areas as the company prepares for "extensive" power outages that could impact up to 500,000 customers, or 70 percent of their system, the company said.

An additional 4,500 line and tree workers were requested to help restore power following the storm. More than 1,300 workers from as far away as the Midwest and Northeast are currently en route to the region, the company said.

Customers, who should contact customer service only if outages last more than 15 minutes, can monitor outages in their neighborhoods through TECO's outage map.