Flood mapping is an inexact science. Past performance is never an entirely accurate predictor of future results. And when it comes to the flood maps that were drawn up for Nassau and Suffolk counties in 2009, it turns out that thousands of residents of Valley Stream, Massapequa Park and some other communities that saw their rates for flood insurance skyrocket were right to complain: Superstorm Sandy proved their assertion that, at least with this particular, quite serious catastrophe, they were not in a flood zone.
The biggest complaint about the new maps was that they covered both counties, but took into account only new scientific surveys of Suffolk, which were used to extrapolate zones for Nassau. The Federal Emergency Management Agency felt that was good enough, but many residents whose premiums increased from as little as $300 to as much as $3,000 disagreed, and many elected officials sided with them.
Yet the only community angry enough to challenge the new maps in court was the Village of East Rockaway, which lost the case, then saw massive devastation from the storm. So it seems complaining about flood maps is as inexact a science as drawing them.
The 2009 maps added about 20,000 Nassau properties to the flood zone. The projection is that information from Sandy will help inform a coastal analysis already in progress, and will allow about 4,500 of them to be dropped from the high-risk area. That leads to the conclusion that about 75 percent of the Nassau additions, though they were based on Suffolk data, were appropriate.
Thanks to a federal law spearheaded by Sen. Charles Schumer (D-N.Y.) and passed last summer, FEMA was already drawing up new maps for Nassau based on its own topography, and the process will now continue with more hard data from Sandy to bolster the computer models. That's fine. More data and better maps are nothing but positive.
But property owners who are removed from the highest-risk -- and highest-insurance cost -- flood zones should still consider buying the federal flood insurance. And those who remain in the high-risk zone and continue to receive quotes of thousands per year for coverage would be wise to buy the insurance even if they don't have a mortgage that requires it. Storms bigger than Sandy, and ones that directly hit different shore points, at different angles and with different wind fields, are always possible, and no flood map is ever final.