(Courtesy New York City mayor’s office)

As Hurricane Irene heads north and President Obama declared a federal emergency in New York City and Long Island, New York Mayor Michael Bloomberg announced Friday that all people living in low-lying areas of the city should evacuate by Saturday afternoon.

In a series of televised announcements, tweets and Facebook messages, the mayor advised people to leave as quickly as possible. Evacuations will be difficult Saturday as all mass transit will be shut in the city by 12 p.m.

The above map divides the city into evacuations zones. Zone A, comprising parts of Battery Park City, Staten Island and Coney Island, are ordered to leave their homes for higher grounds immediately.

People in buildings taller than 10 stories are advised to tape up their windows or move to lower floors, to prevent damage from flying debris. Much of Manhattan has buildings far taller than 10 stories.

In the face of New York cynicism, the mayor’s office took a hard-line approach, sending off increasingly urgent tweets to encourage people to leave.

Hurricane Map English