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Sea, Lake, and Overland Surges from Hurricanes (SLOSH)

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Fri, 2014-03-21 20:59 — Kathy Gilbeaux

nhc.noaa.gov

SLOSH Model - Introduction

The Sea, Lake and Overland Surges from Hurricanes (SLOSH) model is a computerized numerical model developed by the National Weather Service (NWS) to estimate storm surge heights resulting from historical, hypothetical, or predicted hurricanes by taking into account the atmospheric pressure, size, forward speed, and track data. These parameters are used to create a model of the wind field which drives the storm surge.

The SLOSH model consists of a set of physics equations which are applied to a specific locale's shoreline, incorporating the unique bay and river configurations, water depths, bridges, roads, levees and other physical features.

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Fri, 2014-03-21 21:34 — Kathy Gilbeaux

The SLOSH description takes into account the atmospheric pressure, size, forward speed, and track data. These parameters are used to create a model of the wind field which drives the storm surge.
 
The SLOSH model consists of a set of physics equations which are applied to a specific locale's shoreline, incorporating the unique bay and river configurations, water depths, bridges, roads, levees and other physical features.  If there have not been any new coastal barrier infrastructures built in southeast Texas between 2002 and 2008, the assumption is made that the models are based on all of the above information, and were up-to-date in the Hurricane Ike example.
 
It was not well-known in 2008 that the diameter of the storm would be such a huge factor in the height of the storm surge.  The SLOSH models currently factor in the diameter, however it is not certain whether diameter was included as a factor back in 2008.  If it was not included, then that would explain why the SLOSH models for Ike were so inaccurate.
 
Historical SLOSH simulation for Ike (see the link below).
 
The individual SLOSH model image for Ike was the model for the predicted highest water (see the link below).
 
The water depth of the various models in the loop, as well as the highest water point is nearly 10 feet lower than what actually occurred (a serious discrepancy).

Ike made landfall with the highest (recorded) surge of 22 feet coming ashore at Sabine Pass (almost double this SLOSH model).  Damage reports from the field indicate the surge was much higher than 22 feet in some places.

Effects of Hurricane Ike in Texas
 
NOAA - Storm Surge Estimates from Damage Surveys
 
The SLOSH Texas Storm Surge models on the Wunderground website show the worst case scenario (maximum water depth / maximum storm tide) for each category, and is much closer to what occurred during Ike.
Mon, 2014-06-02 22:39 — Kathy Gilbeaux

climatecentral.org - by Andrea Thompson - June 2, 2014

When Hurricane Sandy struck the Northeast, it was not the storm’s winds but the massive pile of water those winds pushed in front of the storm that wreaked the most havoc, inundating coastal areas in 3 to 9 feet of water, causing billions in damages, and leaving dozens dead. In general, this storm surge poses a far greater threat to lives and property than winds when hurricanes and tropical storms hit.

It’s with this in mind that the National Hurricane Center (NHC) has developed an experimental system that maps the projected storm surge in areas under threat from tropical cyclones — just in time for this hurricane season, which began on Sunday, June 1.

(READ COMPLETE ARTICLE)

CLICK HERE - Experimental Potential Storm Surge Flooding Map

CLICK HERE - Experimental P-Surge 2.0: Probabilistic Hurricane Storm Surge (with tide)

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