More than 500 Ameren Illinois Utilities (AmerenCIPS, AmerenCILCO, AmerenIP) personnel and contractors are waging a challenging battle with the weather and hazardous working conditions to restore electricity service to Northern Illinois customers.

Yesterday, service outages peaked at more than 25,000 customers after the number had been reduced to about 6,000. At 5:20 p.m., the number of Ameren Illinois Utilities (AIU) customers without power has been reduced to about 11,000. In total, about 33,000 customers have had service restored since outages began late Wednesday afternoon.

The weather and difficult working conditions have created additional outages as well as outages of longer durations than what was originally projected. At this time, it is estimated all service will be restored by 6 p.m. today. However, outages may last longer if weather and working conditions deteriorate.

"We are appreciative of the patience our customers have shown, but understand they want their service restored as quickly as humanly possible. We will be working throughout the night to achieve this goal," said AIU Vice President of Operations Ron Pate.

AIU has activated the Emergency Operations Center (EOC) to direct the service restoration effort. The EOC has deployed a Storm Trailer to the impacted area. A Storm Trailer is a mobile storeroom, stocked with the material field crews need to get the lights back on. Storm Trailers can be moved to central staging sites to provide essential materials to areas with the greatest damage.

The primary cause of the power outages has been due to a phenomenon known as "galloping conductors." Galloping conductors can occur when strong winds blow across ice-coated power lines, causing the lines to move up and down in a violent manner. This movement is known as "galloping," which often results in damage to cross arms on poles, insulators and even the wires. This will result in power outages.

An example of galloping conductors can be seen at IllinoisOutage.com.