Power has been restored to all but 71 Darien residences as of 11 a.m., after 414 homes and businesses were in the dark an hour earlier. Additionally, traffic lights along Noroton Avenue are functioning again, though detours still remain in effect on West Avenue, according to police.

More than 400 Darienites were without power as of 10:05 a.m. Tuesday. The outages have affected homes and businesses.

First Selectman Dave Campbell said the power outages stem from a "blown transformer."

"It's kind of random all over town, but the hardest hit are West Avenue, Ledge Road, Noroton Avenue off the Post Road," Campbell said.

Town Hall, on Renshaw Road, and the Senior Center, on Edgerton Street, have power, and will serve as cooling stations for the town, as temperatures are predicted to climb into the high 90s throughout the day.

The National Weather service issued a heat advisory, saying Tuesday's combination of high temperatures and gradually increasing humidity will result in a heat index between 100 and 104 degrees.

There was no power at the Darien Library early in the business day, but lights came back on at 10:15 a.m., at which point Director Louise Berry said the building would officially re-open to serve the public. It will also serve as another cooling station for the day.

Additional cooling centers are open at the YWCA until 4 p.m. and the YMCA, which will offer showers after 4 p.m.

Town officials are making phone calls to a list of about 80 senior citizens to offer transportation to one of the cooling stations, Campbell said.

"The biggest concern from a public health standpoint is senior citizens, who are a vulnerable population," Darien Police Sgt. Jeremiah Johnson said. "Some may be reluctant to leave their homes, but we're hoping that especially today, they'll seek relief at the cooling centers.

"If anyone has elderly or disabled residents or neighbors, it's a good thing to check on them," Johnson said.

The outages also affected traffic.

Police said three traffic signals were without power Tuesday morning: Noroton Avenue at Hecker Avenue; Noroton Avenue at Interstate-95, Exit 10 southbound; and Noroton Avenue at Ledge Road. They have been restored.

West Avenue is still closed with detours at Stonybrook Road and Old Parish Road, according to police.