Sand fills streets of Long Beach, N.Y.

>> to our east on new york's long island, flooding and wind damage also widespread and residents of long beach are being told not to drink their tap water this morning. nbc's mara schiavocampo is there. mara , good morning.

>> reporter: matt, good morning. you know, the rain has stopped, but we are still getting pounded by very high winds . that's actually why i'm wearing these glasses because we're getting blasted from the sand coming in from the beach. yesterday during high tide this ocean moved through the town like the colorado river . it was raging. one resident said that it had a fury, and what it did was caused a tremendous amount of flooding, and when it receded, this is what it left behind . want to show you what it left behind . a plow came back to create access for vehicles and left this mound of sand that was left behind the water that came in. this is a city street. right now it's totally and completely a beach, and it's like this for blocks and blocks inland. i want to show you some of the damage here to property. you can see that when that water came rushing through town, it caused a tremendous amount of damage, at least up to one story. all of these vehicles that you're seeing, they weren't parked here. they floated here. they were brought here by the force of that water, and it's just reduced these garages to beams and pieces of splintered wood. this really highlights the major concern that officials here and the reason that they set up a mandatory evacuation for this area, because this area in particular was getting storm surge , not just from the ocean on one side, but also from the bay, so there are reports of considerable flooding all over town, and also of power outages. approximately 850,000 homes without power right now, and the power authority is warning that it could be up to ten days before that comes back. the other concern, especially with these winds still as high as they are, we're now in high tide again, and we can see, you know, the beach is not very far. it's about three blocks away. we can see that water churning and still very, very active and the concern is though it's receded for now, there could be a second wave of flooding, if you will, and could exacerbate the problem here for people who are trying to clean up. we have also seen some damage from these high winds , so it wasn't just the flooding. we have seen roofs peeled back, some damage to roofs and windows, furniture strewn about and the like. a lot of cleanup here in manhattan.

>> mara schiavocampo on long beach in long island. talk about people being without power for seven or ten days. we're entering november here, and it gets cold at night in this part of the country. those people will have issues over the next week or so.