UPDATED 10/30/12 12:27 a.m.
FREEPORT, N.Y. (CBSNewYork/AP) -- About 72 percent of all Long Island Power Authority customers were in the dark late Monday, and all roads in Nassau County were deemed unpassable and shut down.
More than 791,000 homes were without power on Long Island as of 11:45 p.m., according to the Long Island Power Authority.
LIPA warned residents to be prepared to be without power for at least 7 to 10 days, according to the utility's website.
The power company said it provides power to about 1.1 million customers in Nassau and Suffolk counties and the Rockaway Peninsula.
Meanwhile, Nassau County officials announced that all roads were closed. They advised that no residents should leave their homes, and no roads were considered safe.
Downed trees littered the streets of Melville, where sirens were a common sound Monday evening.
Pine Lawn Road was closed hours earlier because of so many fallen trees and branches, WCBS 880's Sophia Hall reported. A traffic light hung by a thread, nearly hitting the street below and the few cars still on the road.
WCBS 880's Sophia Hall reports
In Lindenhurst, Riverdale Avenue lived up to its name. A Jeep was halfway submerged on the roadway, Hall reported.
The normally busy Montauk Highway was shut down earlier in the day, with ankle-deep flooding.
Hall reported that it took several tries to get information through LIPA's text messaging system, which is likely inundated with requests.
The Suffolk County Police Department issued a release at 7 p.m. urging cars to stay off the roads unless it is absolutely essential.
Police said many roads have been closed due to flooding, downed trees and power lines and other unsafe conditions.
Various roads south of Montauk Highway are already impassible due to flooding. When the waters rise due to the tide, Suffolk Police said it anticipates most roads south of Montauk Highway will be obstructed.
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Long Island is bracing for a storm surge of up to 10 feet prompting concerns over rising waters and record tides.
"The worst is yet to come," Nassau County Executive Edward Mangano warned Monday.
In Bayville, the Long Island Sound has swells that appear to be six to eight feet high, WCBS 880's Peter Haskell reported at 6 p.m.
Part of Bayville Avenue is underwater and other streets in the area are littered with downed leaves, twigs and branches, Haskell reported.
WCBS 880's Peter Haskell reports from Bayville
"If the high tide and the winds meet all at the same time, it's really producing what we've been talking about, this incredibly dangerous storm,'' Suffolk County Executive Steve Bellone said.
Cars were floating along the streets of Long Beach in Nassau County, which was under a mandatory evacuation order. Flooding had consumed several blocks south of the bay, said Long Beach resident Jay Bochner.
"We had flooding in the morning. There were some cars floating around,'' he said. "I'm afraid it's going to be even higher.''
As of the 4 p.m. hour, flooding above normal records was already reported in some areas of Nassau County, Mangano said. The situation will get even worse when after landfall occurs, and once high tide arrives between 7 p.m. and 11 p.m.
"This is the time to get out of harm's way and let our first responders do the job that they're trained to do," Mangano said.
Bellone said flooding went all the way to Montauk Highway.
Earlier in the day, 14 people were evacuated from Fire Island – which officials ordered cleared effective at 2 p.m. Sunday. One police vehicle was lost during the evacuation process, but assets provided by the state ensured that the evacuation was successful, Bellone said.
Fire Island has thousands of residents during the summer, but this time of year it's mostly empty. Between 2,000 and 3,000 people live in Fire Island year-round.
Canals already were bulging two hours before high tide around Long Island's Great South Bay area. As early as 7 a.m. Monday, water was about a foot deep on some streets in Lindenhurst.
"All day today will be about the water, about the surges, about the beach erosion and then we will go into full high-gear with our tree-cutting crews once the intensity of the storm passes," Town of Hempstead Supervisor Kate Murray said.
In Wantagh, water was across the roads leading to Jones Beach State Park.
1010 WINS' Mona Rivera reports from Bayville
In Bayville, waves from the Long Island Sound crashed over a sea wall, flooding the beach and a playground.
"We're looking at something worse than anything that we've seen in our lifetime," Freeport Fire Chief David Baer said.
Mandatory evacuations were ordered for residents of Fire Island and in surge zone areas in Babylon, Islip, Brookhaven, Riverhead, Southampton and Southold.
1010 WINS' Holli Haerr reports
While the evacuation is mandatory police said people who chose to stay will not be forcibly removed, but they added that refusing to leave is risky.
"If they choose to stay they're on their own," Ocean Beach Police Chief George Hess said. "We're going to shut down the police department, the fire department and EMS services."
Mangano ordered a mandatory evacuation at 2 p.m. Sunday for storm surge areas along the north and south shores. All of Long Beach, Lido Beach, Atlantic Beach and Point Lookout are under the mandatory evacuation order.
1010 WINS' Carol D'Auria reports from Long Beach
"Many are moving, but of course there are those that always ignore the warnings," Mangano said. "We again appeal to them, if they are not concerned for their own public safety please think about our first responders and remove yourself from the anticipated zones."
"Our concern are the high tides in the evening will be coupled with the high wind advisory that we're expecting here beginning with hurricane gusts as early as 1 p.m. today and then continuing over into Tuesday," Mangano said. "This is a very concerning event, a very dangerous storm, we need to take the precautions that we put out."
American Red Cross shelters have been opened throughout Nassau and Suffolk Counties.
"Follow the warnings; they're out there for a reason," John Miller with the American Red Cross. "We're working cooperatively with our partners in both Suffolk and Nassau County to insure that we have proper coverage. And listen to the wordings, watch the news and be informed."
In Nassau County, shelters were opened at Nassau Community College, Levittown Memorial High School, Locust Valley High School and SUNY Old Westbury.
In Suffolk County, shelters were opened at Hampton Bays High School, Sachem East High School and the Brentwood High School Sonderling Building.
North Shore-LIJ's Center for Emergency Medical Services ordered its ambulances off the road at 4:30 p.m. Monday, when sustained winds began to exceed 50 mph, the hospital announced Monday evening.
In eastern Suffolk County, crews assisted in the evacuation of 26 patients from Eastern Long Island Hospital in Greenport, bringing them to Stony Brook University Medical Center and Peconic Bay Medical Center in Peconic, NY.
LIPA said crews from Iowa, Wisconsin, Illinois, Texas assisting in the storm effort and are reaching out for additional crews throughout the U.S. and Canada.
Chief Operating Officer Michael Hervey is warning customers to be prepared for long-duration outages, lasting as long as seven to 10 days.
"We are going to attempt to restore power during the storm until it's unsafe for the crews to be on the street," Hervey said. "When we get into high winds we'll have to call the crews and ask them to stand down. Once we get past the most windy part of the storm then we can start to survey the damage and do restoration."
To report an outage customers can call 800-490-0075 or go on the utility's website.
Long Island Rail Road service was suspended Sunday night. It is unclear how long service will remain suspended.
New York state has launched its Hurricane Sandy Helpline for residents dealing with the effects of the large and potentially dangerous storm.
Residents can call 1-888-769-7243 or 1-518-485-1159 for information about preparing for the hurricane and its impact. It began hitting New York Monday and is expected to cut a path through the state over the next couple of days.
Information will also be available for referrals to county offices and American Red Cross shelters and about road closures.
Updates via cellphone and computer are also available from NY-ALERT. Register on the NY-ALERT website at www.nyalert.gov. For people without access to the web, call 1-888-697-6972.
(TM and Copyright 2012 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2012 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)
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