OEM Maps, Models Got Sandy Wrong

The city's Office of Emergency Management used National Oceanic and Atmospheric Administration data models to divide the city's low-lying and coastal areas into three zones based on flooding risk.

Zone A is at risk of flooding in any hurricane. Zone B could flood during category 2 or higher hurricanes. Zone C could flood during a Category 3 or 4 hurricane that strikes just south of of New York City.

The Sunday before Hurricane Sandy hit, Mayor Bloomberg ordered people living in Zone A to evacuate.  He didn't mention Zone B.

But when the storm hit, neighborhoods in Zone B: Canarsie, Gravesend, Gerritsen Beach, Bergen Beach, portions of Bath Beach, Mill Basin, Marine Park, all flooded.

The ten-year-old data OEM used to create its maps was updated only to add the Rockaways, City Island and Hamilton Beach to Zone A after Hurricane Irene in 2011.

The Federal Emergency Management Administration's Flood Hazard Area maps include parts of South Brooklyn omitted from OEM's Zone A: Gerritsen Beach, the Canarsie waterfront, East New York, Starrett City, Mill Basin, Howard Beach, parts of Bath Beach and most of Bergen Beach.

Within 80 years, a four-foot sea-level rise is projected.  Rising sea levels due to climate change means far more severe weather events in the future. Sandy was just the first of the superstorms.

If, in the meantime, the city continues developing its waterfront, more people will be at risk of storm surges, particularly if the sewer system isn't upgraded.

The post from City Limits.

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