Connecticut received a significant amount of the strongest winds from Tropical Storm Isaias from the southeast side of the system. Peak wind gusts reached as high as 68 mph in Bridgeport and 66 mph in New Haven.
At one point Wednesday, more than 715,000 people were without power in the state after hundreds of trees and power lines came down. That number has since come down but remains over 600,000 early Thursday.
Tropical Storm Isaias produced the third largest number of outages on record statewide for Eversource customers. It is third behind the October snowstorm and Tropical Storm Irene.
On Wednesday, nearly half of Eversource's customers were without power, including some towns where 100% of the town needed to be restored. Eversource officials estimate it could take multiple days before power is fully restored.
"We're asking our customers to prepare for multiple days without power," Eversource spokesman Mitch Gross told NBC Connecticut's Kevin Nathan. "We're working as quickly and as safely as we can, and there's a lot of damage out there and a lot of work that still needs to be done."
The company said it is working around-the-clock shifts to clear roads, assess damage and restore power, however it still is not providing estimates for restoration.
"We have extensive damage throughout the state," Eversource responded to one customer on Twitter. "Our crews are working around the clock to restore as quickly and safely. We are still assessing the damage as well. Therefore, we know it will be multiple days, but we are unable to provide an ETR at this time."
If you are experiencing an outage and are an Eversource customer, you should call 800-286-2000. You can also report your outage online.
United Illuminating also said they believe restoration may take several days.
“The restoration effort that is already under way is likely to last several days, and customers who are currently without service should factor that in their planning,” the company said in an email to customers on Tuesday night.
Additional contractors and mutual assistance is being brought in from other utilities to help UI crews with the restoration, UI said.
UI customers experiencing an outage can report it by calling 800-722-5584.
Residents are urged to stay far away from downed wires and are reminded to always report them to their power company.