While Hurricane Irene was downgraded to a tropical storm Sunday morning, it hit New York City and New Jersey with wind, rain and flooding waters.

Authorities warned that the impact of Irene was not waning, as the storm left 3 million people in the Northeast without power and claimed at least 11 deaths.

The Hudson River overflowed, spilling water over streets and waterfront buildings in lower Manhattan, potentially forcing a power shutdown for days. Serious flooding was reported in Brooklyn as well.

Battery Park City hasn't seen a massive flood yet, as the water level remains just one foot below the top of the protective wall, according to the latest estimate from the office of Emergency Management, reported DNA Info.

However, South Street is impassable among other blocked streets, and seawater rushed toward the deserted Wall Street.

The storm pushed a 3 1/2-foot surge of water into New York Harbor and forecasters said the peak could be twice as tall later in the morning, reports USA Today.

The challenge of New York is that so much of the electricity and other infrastructure is below the surface, former Homeland Security Secretary Michael Chertoff told CNN.

The worst of Hurricane Irene to hit the city was in the early morning hours, between 4 a.m. and 4 a.m., when Brooklyn and Queens heard tornado warning sirens sound amid whipping wind of 40 to 50 miles per hour at times. Trees but, windows rattled and heavy rains fell, but New York City stood tall and strong.

The north tube of the Holland Tunnel has been closed due to flooding.

Due to flooding conditions, the southbound Henry Hudson Pkwy is closed at W 125th St in MN. Expect extensive traffic delays, tweeted NYC Mayors Office Sunday morning.

The Belt Parkway is closed in both directions at Bay 8th St in Brooklyn, the same source said in an earlier Twitter message.

New Yorkers are urged to call 311 to report downed trees, and damage or flooding to their homes.

Updates on the weather and street conditions can be reported and found here:

http://nycsevereweather.crowdmap.com/

Hurricane Irene forced an unprecedented evacuation order for New York City's coastal areas that cover 250,000 residents in Coney Island and Manhattan Beach in Brooklyn, Far Rockaway and Broad Channel in Queens, South Beach, Midland Beach, and other low-lying areas on Staten Island, Battery Park City in Manhattan, and some small sections of the Bronx.

Officials also elected to shut down New York City's sprawling transit system, which encompasses both the subway and an array of commuter rail lines that serve Long Island, Westchester County and Connecticut, starting on Saturday until further notice.

Sunday morning, Con Edison announced that 72,000 customers in New York City and Westchester County have lost electricity due to severe winds. As the weather system continues to move toward New York, the number of affected customers is expected to grow.

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