A half million Ameren company customers across Illinois and Missouri are out of power today as Ameren officials assess a storm that created the most significant damage in the company's more than 100 years of service.

Damage was most significant in the St. Louis city, county and metro east regions of Illinois. The storm caused extensive tree damage, broken poles and downed wires in addition to the loss of more than 400 distribution feeder circuits-each supplying power to between 500 and 1500 customers.

The storm hit around 7 p.m. last night, with about 450,000 customers remaining without service as of 6 a.m. today (Thursday, July 20). The company has restored service to more than 100,000.

Given the nature of the damage, Ameren companies cannot offer customers anticipated restoration times but will make those available as soon as possible.

"We have called out all Ameren company crews, available contractor crews and are requesting assistance from utility companies throughout the region. We do appreciate our customers' patience during this critical time," said Richard Mark, senior vice president, AmerenUE Missouri Energy Delivery. "We are working closely with city and state officials and emergency response personnel to coordinate restoration efforts and ensure customer safety. Work will be continuing around the clock. Today is expected to be one of the hottest this year, making it critically important that customers stay safe and remain alert to signs of heat exhaustion."