Gov. Chris Christie did what he does best - bring clarity to an issue - by unilaterally enacting new coastal building elevations based on the Federal Emergency Management Agency's new preliminary flood maps, which have caused so much consternation and uncertainty at the shore.

Certainly, as state Sen. Jim Whelan, D-Atlantic, other critics and even Christie himself have noted, the implementation of these new maps and the accompanying new building elevations will be incredibly disruptive, costly and wrenching for many shore residents and towns.

People who cannot afford to raise their damaged homes or to pay the increased flood-insurance premiums that will result from not rebuilding higher could be forced to sell - and at far lower prices than they ever imagined. Towns' ratable bases could suffer as property values drop; taxes could rise for those who remain behind.

FEMA released the advisory base flood elevation maps in December. Many properties were added to so-called velocity zones, where the highest elevations and toughest construction rules apply. But the maps may not be finalized for up to two years, which left many shore towns and property owners unsure of whether to build to the new elevations now or wait.

Christie at least ended that quandary. If you are building or rebuilding now, the new elevations apply. If you did not suffer any major damage from Sandy, you are not technically required to raise your home. However, if you are in a velocity zone and have a mortgage that requires you to have flood insurance, and you don't raise your house, you will see your federal flood insurance premiums rise astronomically in the coming years - to as high as $31,000 a year in some cases, Christie noted.

But it is important to remember that National Flood Insurance Program premiums had been scheduled to rise before Sandy even showed up on meteorologists' radar screens. Last summer, Congress passed several overdue changes to the deeply indebted program to make premiums more accurately reflect actuarial assessments of risk. And FEMA has been working on the new maps for years. This was all coming no matter what, in an effort to better protect coastal properties and to get the flood insurance program on a firmer financial footing. Sandy and Christie's emergency order have simply accelerated a process that was already well under way, although few living along the coast may have realized that.

The new flood maps and new required building elevations are all designed to get the federal government and federal taxpayers out of the business of subsidizing coastal living, which makes sense. The costs of living along the coast must ultimately be borne by those who choose to live here.

The maps are still subject to revision - some V zones could revert to less-stringent A zones - as the federal rule-making process plays out. Individual property owners will have the right to appeal their flood-zone classification.

But there is no doubt that many middle-class people living along the coast will have some brutally tough decisions to make. And that makes these new rules a bitter, bitter pill indeed.