A power outage is affecting more than 550 residential National Grid customers and the lights might not come back on until late this evening.
National Grid reports 554 customers are without power in Portsmouth and on Prudence Island in an outage that occurred after 3 p.m.
The outage covers a northwestern chuck of the island as far east as Quaker Hill and runs from about the intersection of Turnpike Avenue, Bristol Ferry Road and West Main Road to the north and the Lawton Valley Reservoir to the south.
National Grid Spokesman David Graves said the outage occurred when a pole on Melville area went down on Navy Property.
"This is going to be an extended outage because the pole that went down is in a swampy area," Graves said. "It's difficult to get a truck in there simply because getting access to the pole is difficult."
Graves said the pole carries a primary line and there is no redudency available in that area, which prevents the utility company from routing power from another direction to affected customers.
"Unfortunately, it's going to be dark out there for a while," Graves said.
Crews are working to restore power and it is estimated that it should be restored by 10 p.m.