what I don't understand is why they preached and preached how surge and wind are two different aspects of a tropical cyclone then give the public a tool that classifies surge in one broad swoop by the wind category ?
SLOSH has been around for a long time,
http://www.nhc.noaa.gov/surge/slosh.php you can even download the program
http://slosh.nws.noaa.gov/sloshPub/disclaim.php there are so many variables that go into it, however, that I believe releasing a map like that does more harm than good to the general public, who does not have the training
( slosh.nws.noaa.gov/sloshPub/SLOSH-Display-Training.pdf or slosh.nws.noaa.gov/sloshPub/SLOSH-Display-Training.ppt )
to understand the variables - without it, it's a scare map
from their site:
SLOSH Model
The SLOSH model computes storm surge heights from tropical cyclones using pressure, size, forward speed, and track data to create a model of the wind field which pushes the water around. (A portion of the surge is caused by the low pressure at the center of the hurricane, but this effect is small in comparison to the wind effects.) A sample output can be seen here for Hurricane Hugo.
SLOSH has been applied to the entire U. S. East coast and Gulf of Mexico coastlines. In addition coverage extends to Hawaii, Guam, Puerto Rico, and the U. S. Virgin Islands (coverage). An example of a typical compuational domain, or basin, is the Biloxi, Mississippi basin.
Based on tide gage observations and high water marks (HWM) measured after past hurricanes, the SLOSH model is accurate to within +/- 20%. However, there is considerable error in the HWM data. Using higher quality, "excellent" HWMs from Katrina, SLOSH accuracy approached +/- 5%.
The SLOSH model consists of a set of equations derived from the Newtonian equations of motion (shallow water equations) and the continuity equation applied to a rotating fluid with a free surface. The equations are integrated from the sea floor to the surface. The coastline is represented as a physical boundary. Subgrid-scale water features (cuts, chokes, sills and channels), and vertical obstructions (levees, roads, spoil banks, etc.) are parameterized. The model accounts for astronomical tides by specifying an initial tide level, but does not include rainfall amounts, riverflow, or wind-driven waves.
At the time emergency managers must make an evacuation descision, errors in the hurricane's track and characteristics are large. To aid emergency managers in planning for hurricanes, the potential surge for an area is computed. This is done by running SLOSH with hypothetical hurricanes with various landfall directions and locations, Saffir-Simpson categories, forward speeds, sizes, and tide levels. Each individual run generates an envelope of high water containing the maximum value a grid cell attains during the run. These envelopes are then combined by taking the maximum by category, speed and direction to create MEOWs (Maximum Envelope Of Water), or simply by category to create MOMs (Maximum Of MEOWs). The MEOWs and MOMs form the basis of the "hazard analysis" portion of coastal hurricane evacuation plans.
and
----- I acknowledge reading the following -----
The SLOSH Display Program was developed for emergency management and the scientific community to aid in decision making at the local, state and federal level. It is not meant for use by the general public in determining whether to evacuate leading up to a storm. Pay attention to your local emergency manager, particularly during an evacuation.
The SLOSH Display program is only one of several tools used by emergency management agencies to determine who is at risk and may be asked to evacuate. DO NOT disregard the advice of local authorities as the SLOSH Display program is not meant for life or death decision making!
We recommend people have some training. We have some here and we are developing additional training. The key ideas to learn are:
What is storm surge?
There is inaccuracy in any model.
There is more inaccuracy in the input wind parameters to surge models than in the models themselves. 
