Hit by its largest customer outage in 26 years, the Long Island Power Authority said Sunday that it could take at least several days to completely repair the large-scale damage caused by Irene.
About 471,000 LIPA customers spent most of the day Sunday without power, and utility officials said much of the work over the next day will focus on damage assessment and attempts to repair high-level transmission wires, 19 of which were damaged in the storm.
On Monday morning, 419,538 customers remained without power, according to the LIPA websitee.
LIPA chief Michael Hervey said most of the 19 lines had trees fall on them and repairs could be completed by early this morning.
Some 1,500 survey workers began assessing the damage, an essential step before most work can begin, and a force of 630 tree trimmers is expected to be deployed over the next day or two to remove trees obstructing work areas and damaging power lines. The workforce will eventually number 7,500.
Officials could not say precisely when the entire system would be back up. Indeed, without a full assessment of the system, it's still unknown how much damage was inflicted. "The damage is so varied and unknown at this time that it's impossible to give a good answer," Hervey said.
Earlier in the day, Hervey noted that it took six days to restore the 260,000 customers who were out of power after the nor'easter in March 2010. This time, he said, LIPA has the advantage of having outside crews here on the ground.
At a news conference in Long Beach Sunday, Gov. Andrew M. Cuomo said the outages would last "multiple days," while Nassau County Executive Edward Mangano said LIPA told him restoration efforts would take "two to six days."
Estimates of how much it will cost to respond to Irene are not yet available, but Hervey put the cost, based on past storms, at "multimillion-dollars per day."
The difficulty for workers was evident on the heavily tree-lined streets of Mastic Beach, where several narrow roadways were blocked because of arcing or tree-stretched power lines. On Alder Drive, the sound of arcing power lines could be heard for blocks as great yellow flashes pulsed from a tree limb that had fallen onto wires.
In East Moriches, Chris and Carl Sandbeck stood a safe distance from a large old tree on their front lawn that had split in half and fallen across rows of utility lines and onto Montauk Highway, bowing wires like rubber bands.
The 390,000 customers without power are the most since Hurricane Gloria in 1985, when 750,000 lost power. Customers include residences and businesses.
Because little damage was inflicted on local power plants and the natural gas distribution systems, repair employees for those facilities are available to work on LIPA restoration, said John Bruckner, president of National Grid's Long Island Electric Transmission and Distribution Services. National Grid operates the local grid under contract to LIPA.
Substations in a projected tornado zone along the Nassau-Suffolk border have not all been inspected, Hervey said. If there's water damage, repairs could take a week, though LIPA can bring in portable generators to restore power to some customers, he said.
Hervey acknowledged the frustration of customers who have been calling seeking specific restoration times. "Before we can do that, we have to survey the system," he said.Still, he said, repairing transmission lines could reduce a large number of outages at once.