FEMA is in the process of updating the FIRMs in my county. In 2009 they released a set of preliminary dFIRMs and now in 2013 they have released another. These are all coastal floodplains.
The 2009 floodplains were very similar to the 1992/1997 revised FIRMs.
The 2013 floodplains are substantially greater than the previous maps. An estuary located approximately 1 mile from the shore up a somewhat narrow tidal river has floodplain increasing by 5'. There is some shoreline that has no fetch with a new floodplain of 28 with adjacent floodplains of 13-18.
On the 7th, FEMA will have a 5-hour information session to discuss the changes. As we have not had a 100-year storm in many decades, it makes it difficult to comprehend such heights. We have recorded many of the peak flood elevations after the more significant storms in the past two decades and none of the heights have been close.
For those living and working within areas that have endured substantial storms, how close have these storms come to the old floodplains? How about the new ones?
Welcome to climate change. Flood zones will continue to rise and broaden as well, as FEMA's 2013 recomputations only account for the increased sea level, increased intensity of storms, and increased precipitation of the past 37 years.
...FEMA officials said they are aware that storms are becoming more frequent and more intense from climate change, and that the flood zones could change as a result. The agency rushed to release the redrawn maps last week because despite possible flaws, they're more precise than the 1986 maps and are needed for the Sandy recovery process.
The maps are preliminary and can't be used to enforce new building laws until approved by the New York City Council and government officials in surrounding areas.
Property owners in high-risk zones could be required to elevate their buildings an average of three to six feet on poles or take other action to protect their structures from flooding. Building owners who don't comply with the new flood guidelines could face sharp increases in insurance premiums. FEMA officials estimate that annual insurance rates for single-family homes that don't meet the guidelines could jump from $1,400 to an estimated $9,500 a year, according to media reports.
Orton said FEMA should make it clear to property owners that the new maps don't anticipate future problems caused by climate change.
"If you're planning for 50 years in the future, which is at least how long houses can last, it wouldn't hurt to anticipate a few more feet of sea level rise and build appropriately," he said....
Big Government Conspiracy™ to hydrologically extort the citizenry? Private Sector insurers have been busy as little beavers adjusting their actuarial tables to account for their increased exposure...
Increasingly, weather and climate related catastrophes are costing insurers. The number of weather-related loss events in North America has nearly quintupled in the past three decades, according to a recent report from MunichRe. Sandy alone cost New York and New Jersey $80 billion, affecting individuals and business, and impacting health. Claims have more than doubled each decade since the 1980s (adjusted for inflation) and paid claims now average $50 billion a year worldwide.
Many insurers are using climate science to better quantify and diversify their exposure, more accurately price and communicate risk, and target adaptation and loss-prevention efforts. They also analyze their extensive databases of historical weather- and climate-related losses, for both large- and small-scale events. But insurance modeling is a distinct discipline. Unlike climate models, insurers’ models extrapolate historical data rather than simulate the climate system, and they require outputs at finer scales and shorter time frames than climate models.
http://arstechnica.com/security/2012/12/climate-change-is-big-business-for-the-insurance-industry/
Insurance companies have been paying out a lot in claims lately......they need to recoup that expense......increasing the flood plain will increase revenue......it's all about the Benjamins.......more work for us too.....
The question is a scientific one turned political then. I have clients who want to know how likely a 28' surge is when their neighbors only have a 13 to deal with. Seems kinda unlikely that the storm will cause such radical variations in such a small range.
The answer may come from Hurricane Sandy, which together with Katrina, has left a 20 Billion Dollar deficit in the National Flood Insurance Program
Congress has mandated that money be paid back to the U.S. Treasury by the Biggert-Waters Flood Insurance Reform Act of 2012.
FEMA doesn't have printing presses for money, like the U.S. Mint has. It has to come up with that money from someone...... It's under a Congressional Mandate to do so.
Great, and SuperStorm Sandy caused a storm surge that:
A) Exceeded expected flood elevations
B) Was equal to expected flood elevations
C) Was less than expected flood elevations
How about Katrina? Granted that one had other issues at hand.
A) Exceeded expected flood elevations
B) Was equal to expected flood elevations
C) Was less than expected flood elevations
Any other substantial coastal storms worth noting?
What areas are due? I know Cape Cod has been fortunate, especially with that odd hook Sandy took, but we are now due for a big one.
Our zoning bylaw has a 50' setback to flood plain and our Conservation Commission has a 50' 'No disturb zone'. Somewhere in the vicinity of 10% of the properties in Town will be within the flood plain when these maps go into effect. Permitting will become more difficult as we are also not allowed to fill within the flood plain.