A rare October snowstorm has claimed the life of one individual and caused nearly 500,000 customers to lose power, Gov. Dannel P. Malloy said Saturday evening. The number of customers without electricity is expected to climb to more than 550,000 overnight.

Malloy didn’t know much about the death except to say that it occurred on Route 85 in Colchester.

As for the power outage, Malloy said both Connecticut Light & Power and United Illuminating have crews out addressing emergency situations.

“Those crews are for emergency conditions,” Malloy said. “Wires down on the street, arcing situations, limbs making streets impassable — that‘s the work being done tonight.”

Connecticut Light & Power said in a press release that it has more than 200 line and tree crews working Saturday and has called in help from other states.

“If you are without power you should expect to be without power for a prolonged period of time,” Malloy said in a briefing at the Emergency Operations Center in the state Armory. “Repair work will not begin until there are safer conditions for that work to occur.”

The outages are increasing at a rate of about 50,000 to 75,000 per hour, Malloy said.

“If you’re without power you’re going to be without power for a prolonged period of time,” Malloy said. “It’s not coming back on tonight in all likelihood and we’ll have more to report on that tomorrow morning.”

During Hurricane Irene this past August it took CL&P and United Illuminating more than a week to restore power to nearly 800,000 customers.

“As was predicted, the heavy, wet snow is weighing down the trees and creating issues across the state,” Al Roy, CL&P’s manager of emergency management, said. “Our crews and support staff continue to respond as the storm moves through and we are communicating with town and state officials to coordinate efforts.”

The number of customers without power is expected to increase to 550,000 overnight, which means the state will experience more outages than it did during Hurricane Gloria, Malloy said.

In addition to the large number of residents without power, there were a large number of spinouts that led to traffic stoppages on I-95, Malloy said.

Malloy shut down the Merritt and Wilbur Cross Parkways to all non-emergency vehicle traffic around 3:30 p.m. Saturday, leaving I-95 as the only other alternative for those traveling in that part of the state.

Malloy said all 600 state plow trucks and 40 contractors are out clearing the state’s roads and highways. He said they are responding to a winter storm in the normal way.

MetroNorth was experiencing extensive delays, 23 planes have been diverted to Bradley International Airport, and bus service in Danbury and Waterbury was canceled Saturday.