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 are without power: Noroton Avenue at Hecker Avenue; Noroton Avenue at Interstate-95, Exit 10 southbound; and Noroton Avenue at Ledge Road.

As of 10:05 a.m., CL&P reported that 414 Darien residents were affected by the outage.