2. Storm Surge Definitions:
STORM SURGE is the increase in water level due to a storm (hurricane)
STORM TIDE is the total water level measured above a reference datum during a storm (the combination of astronomical tide and storm surge).
EXTRATROPICAL STORM SURGE is the storm surge due to a storm that forms outside of the tropics. A typical example would be a “Nor’Easter”.

3. Tide with Storm Surge DUNE DUNE STORM SURGE STORM SURGE STORM SURGE
HIGH TIDE
STORM SURGE
STORM SURGE
STORM SURGE
MEAN TIDE (MSL)
LOW TIDE

4. b. Side view of Cross Section “ABC”
DEEP WATER
a. Top view of Sea Surface
b. Side view of Cross Section “ABC” A B C
Wind
Eye A B C 0’
5O’
100’
150’
200’
MSL
Current

5. b. Side view of Cross Section “ABC”
LANDFALL
a. Top view of Sea Surface and Land
b. Side view of Cross Section “ABC”
Sand Dunes
on Barrier
Island A B C
Wind
Wind
Wind
STORM SURGE
Eye 0’
5O’
100’
150’
200’
MSL A B
Current C
Barrier
Island
Mainland
Continental Shelf

7. Individual Grid Sub-grid elements:
1 dimensional flow for rivers and streams
Barriers
Cuts between barriers
Channel flow with chokes and expansions
Increased friction for trees and mangroves
Individual Grid
Barrier
Stair Step Rise
Water Surface
above a square
Transport
Points
Water Depth
above a square
Surge Points
DATUM

15. SLOSH Basins

16. Wind Input To SLOSH Embedded parametric hurricane wind model requires:
TRACK Positions - Latitude & Longitude
INTENSITY of the Storm - (change in pressure) (not observed wind speed)
SIZE of the Storm - Radius of maximum wind
Wind Model solves a differential equation for wind speed and direction
Forward speed is incorporated into asymmetry.
Advantages:
Universal (not “calibrated” to location)
Utilizes “forecastable” hurricane parameters (Does have errors)
Tested on many past hurricanes

17. SLOSH Model
Model runs and creates a rexfile and an “envelope of high water”. The “Envelope” is the highest the water got in a particular grid cell during the Model run.
Designed for use with hurricane evacuation planning
MEOW: Maximum Envelope of Water
Highest water due to a family of parallel tracks with same direction, speed and intensity
MOM: Maximum of MEOWs
Highest water due to a set of MEOWs.
Rex File: Enables us to start to use it for real-time storm surge forecasting. (only used about 12 hours before projected landfall)
FEMA HLT (Hurricane Liaison Team)
Intent is for first response and recovery
Convert envelope in real time to ESRI ArcGIS .shp files
Used as input to hydrology’s DWOPER river model
Historical hurricane runs