FEMA has been creating updated flood maps for years, using modern "LIDAR" ground mapping done with lasers from airplanes to accurately determine property elevations, and using advanced new computer models to predict the risk of flooding. Existing maps date back to the 1980s and earlier, and are often crude approximations based on little more than guesswork. But the new high-tech maps don't tend to please coastal dwellers: As the process moves from region to region, news reports are full of complaints from property owners who find themselves in a higher flood risk category for the first time.
But it doesn't always work out that way. Sometimes, the new maps for a location indicate a reduced risk. In one recent example, thousands of homes in coastal Dare County, North Carolina find themselves outside the newly re-drawn flood-plain, after paying mandatory flood insurance premiums for years. The Virginian-Pilot has a report (see: "New OBX flood maps could mean insurance savings," by Jeff Hampton).
"If the new maps are approved, more than 22,000 Dare County homes would sit outside areas now marked as prone to heavy flooding where more-expensive insurance is required. More than 6,000 homes would be removed from flood zones in Currituck County," the paper reports.
It's happening on the West Coast also. In Cannon Beach, Oregon, the new flood maps might be "the greatest unintentional gift the city has ever received," reports the Daily Astorian ("Newly revised FEMA maps will favor city properties," by Erick Bengel. "An early draft of the maps, released last December, reveals a gigantic change from the current 2010 maps: Virtually the entire downtown area has been removed from the 100-year flood plain, a.k.a., the Special Flood Hazard Area," the paper reports. "This means that, when the maps go into effect (probably in 2016), most of the city's downtown property owners will no longer be required by their commercial lender to purchase flood insurance."