Hurricane Ike: Observations and Analysis
 

of Coastal Change
 

USGS Open-File Report 2009-1061
 

By Kara S. Doran, Nathaniel G. Plant, Hilary F. Stockdon, Asbury H. Sallenger, and Katherine A. Serafin 

 

Hurricane Ike: Observations and Analysis of Coastal 

Change 

By Kara S. Doran, Nathaniel G. Plant, Hilary F. Stockdon, Asbury H. Sallenger, and Katherine A. Serafin 

Open-File Report 2009–1061 

U.S. Department of the Interior 

U.S. Geological Survey 
 

 

 

 

 

 

U.S. Department of the Interior 

KEN SALAZAR, Secretary 

U.S. Geological Survey 

Suzette M. Kimball, Acting Director 

U.S. Geological Survey, Reston, Virginia 2009 

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Telephone: 1-888-ASK-USGS
 

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its natural and living resources, natural hazards, and the environment:
 

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Telephone: 1-888-ASK-USGS
 

Suggested citation:
 

Doran, Kara S., Plant, Nathaniel G., Stockdon, Hilary F., Sallenger, Asbury H., Serafin, Katherine A., 2009, Hurricane 

Ike: Observations of Coastal Change: U.S. Geological Survey Open-File Report 2009-1061.
 

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endorsement by the U.S. Government.
 

Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report.
 

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Contents
 

1. Introduction................................................................................................................................................................ 1
 

2. Storm Overview ......................................................................................................................................................... 2
 

2.1 Storm History ....................................................................................................................................................... 2
 

2.2 Extent of Hurricane-Force Winds ......................................................................................................................... 2
 

2.3 Offshore Wave Climate........................................................................................................................................ 3
 

2.4 Storm Surge......................................................................................................................................................... 4
 

3. USGS Coastal-Change Observations........................................................................................................................ 5
 

3.1 Oblique Aerial Photography and Video observations ........................................................................................... 5
 

3.2 Lidar Topographic Surveys .................................................................................................................................. 6
 

3.2.1 Lidar Flight Information.................................................................................................................................. 7
 

3.2.2 Lidar Control GPS Base-Stations .................................................................................................................. 7
 

3.2.3 Lidar Quality .................................................................................................................................................. 8
 

4. Coastal-Change Analysis .........................................................................................................................................10
 

4.1 Photo Comparison Analysis ................................................................................................................................10
 

4.1.1 Surfside Beach to San Luis Pass, Texas......................................................................................................10
 

4.1.2 Galveston, Texas .........................................................................................................................................14
 

4.1.3 Bolivar Peninsula..........................................................................................................................................18
 

4.1.4 High Island to Sabine Pass, Texas...............................................................................................................21
 

4.1.5 Cameron Parish, Western Louisiana............................................................................................................25
 

4.2 Quantitative Topographic-Change Analysis ........................................................................................................28
 

4.2.1 Dune Elevation Change................................................................................................................................31
 

4.2.2 Shoreline Change.........................................................................................................................................32
 

4.2.3 Beach-Volume Change ................................................................................................................................32
 

5. Acknowledgments.....................................................................................................................................................33
 

References Cited..........................................................................................................................................................34
 

Figures 

Figure 1. Track of Hurricane Ike in the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. .................................... 2
 

Figure 2. Wind speeds in kilometers per hour generated by Hurricane Ike, as calculated by the National Oceanic and
 

Figure 3. Significant wave height during the passage of Hurricane Ike, as measured from National Oceanic and
 

Figure 4. Digital-photography and video and recording system used aboard aircraft during coastal oblique video and
 

Figure 5. Hurricane Ike pre- and post-storm oblique aerial photography and video flights and post-storm lidar 

Atmospheric Administration Hurricane Research Division................................................................................ 3
 

Atmospheric Administration Buoy 42035 located near Galveston, Texas......................................................... 4
 

photography missions....................................................................................................................................... 6
 

coverage........................................................................................................................................................... 8
 

Figure 6. Map of Galveston Island. .............................................................................................................................. 9
 

Figure 7. Relative offset between 2005 and 2008 Experimental Advanced Airborne Research Lidar first-return 

lidar...................................................................................................................................................................10
 

Figure 8. Location index for photo pairs from Surfside Beach, Texas to Cameron Parish, Louisiana......................11
 

Figure 9. Oblique aerial photography from Quintana, Texas, on September 9, 2008 and September 15, 2008, two
 

days after landfall of Hurricane Ike ..................................................................................................................12
 

Figure 10. Oblique aerial photography from Christmas Bay, Texas, on September 9, 2008, and September 15, 2008, 

two days after landfall of Hurricane Ike............................................................................................................13
 

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Figure 11. Oblique aerial photography of Galveston, Texas, on September 9, 2008, and September 15, 2008, two 

days after landfall of Hurricane Ike ..................................................................................................................15
 

Figure 12. Oblique aerial photography of Galveston, Texas, on September 9, 2008, and September 15, 2008, two 

Figure 13. Oblique aerial photography of Galveston, Texas, on September 9, 2008, and September 15, 2008, two 

Figure 14. Oblique aerial photography of Bolivar Peninsula, Texas, on September 9, 2008, and September 15, 2008, 

Figure 15. Oblique aerial photography of Bolivar Peninsula, Texas, on September 9, 2008, and September 15, 2008, 

Figure 16. Oblique aerial photography near McFaddin Wildlife Refuge, Texas, on September 9, 2008, and
 

Figure 17. Oblique aerial photography near McFaddin Wildlife Refuge, Texas, on September 9, 2008, and
 

Figure 18. Oblique aerial photography near McFaddin Wildlife Refuge, Texas, on September 9, 2008, and
 

Figure 19. Oblique aerial photography from Cameron Parish, Louisiana, on September 9, 2008, and September 15, 

Figure 20. Oblique aerial photography from Peveto Beach, Louisiana, on September 9, 2008, and September 15, 

days after landfall of Hurricane Ike ..................................................................................................................16
 

days after landfall of Hurricane Ike ..................................................................................................................17
 

two days after landfall of Hurricane Ike............................................................................................................19
 

two days after landfall of Hurricane Ike............................................................................................................20
 

September 15, 2008, two days after landfall of Hurricane Ike .........................................................................22
 

September 15, 2008, two days after landfall of Hurricane Ike .........................................................................23
 

September 15, 2008, two days after landfall of Hurricane Ike .........................................................................24
 

2008, two days after landfall of Hurricane Ike..................................................................................................26
 

2008, two days after landfall of Hurricane Ike..................................................................................................27
 

Figure 21. Oblique aerial photography from Holly Beach, Louisiana, from 2001-2008. ..............................................28
 

Figure 22. September 2005 Experimental Advanced Airborne Research Lidar first-return lidar digital elevation model 

of Crystal Beach, Texas...................................................................................................................................29
 

Figure 23. September 2008 Experimental Advanced Airborne Research Lidar first-return lidar digital elevation model
 

of Crystal Beach, Texas...................................................................................................................................30
 

Figure 24. Coastal change at Crystal Beach, Texas due to Hurricane Ike. .................................................................31
 

Figure 25. Hurricane Ike dune-elevation change, shoreline change, and beach-volume change. ..............................33
 

Tables
 Table 1. Details of the two GPS control stations used during the September 17-18, 2008, EAARL lidar mission. .. 7
 

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Conversion Factors
 

SI to Inch/Pound 

Multiply By To obtain 

Length 

centimeter (cm) 0.3937 inch (in.) 

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi) 

kilometer (km) 0.5400 mile, nautical (nmi) 

meter (m) 1.094 yard (yd) 

Volume 

cubic meter (m3) 6.290 barrel (petroleum, 1 barrel = 42 gal) 

cubic meter (m3) 264.2 gallon (gal) 

cubic meter (m3) 0.0002642 million gallons (Mgal) 

cubic decimeter (dm3) 0.03531 cubic foot (ft3) 

cubic meter (m3) 35.31 cubic foot (ft3) 

cubic meter (m3) 1.308 cubic yard (yd3) 

Flow rate 

kilometer per hour (km/hr) 0.6214 mile per hour (mi/hr) 

Additional Abbreviations and Acronyms
 

ACRONYM OR ABBREVIATION DEFINITION 

CORS Continuously Operating Reference Stations 

DEM Digital Elevation Model 

EAARL Experimental Advanced Airborne Research Lidar 

GPS Global Positioning System 

Hz Hertz 

v 
 

 

 

 

kHz Kilohertz 

KGLS Scholes International Airport at Galveston 

KPKV Calhoun County Airport 

Lidar Light Detection and Ranging 

NAD83 North American Datum 1983 

NAVD88 North American Vertical Datum 1988 

NHC National Hurricane Center 

nm Nanometer(s) 

NOAA National Oceanic and Atmospheric 

Administration 

NWC National Weather Center 

USGS U.S. Geological Survey 

UTC Coordinated Universal Time 

vi 
 

 

 

 

 

 

 

 

 

Hurricane Ike: Observations and Analysis of Coastal 

Change 

By Kara S. Doran, Nathaniel G. Plant, Hilary F. Stockdon, Asbury H. Sallenger, and Katherine A. Serafin 

1. Introduction 

Understanding storm-induced coastal change and forecasting these changes require knowledge 

of the physical processes associated with the storm and the geomorphology of the impacted coastline. 

The primary physical processes of interest are the wind field, storm surge, and wave climate. Not only 

does wind cause direct damage to structures along the coast, but it is ultimately responsible for much of 

the energy that is transferred to the ocean and expressed as storm surge, mean currents, and large waves. 

Waves and currents are the processes most responsible for moving sediments in the coastal zone during 

extreme storm events. Storm surge, the rise in water level due to the wind, barometric pressure, and 

other factors, allows both waves and currents to attack parts of the coast not normally exposed to those 

processes. 

Coastal geomorphology, including shapes of the shoreline, beaches, and dunes, is equally 

important to the coastal change observed during extreme storm events. Relevant geomorphic variables 

include sand dune elevation, beach width, shoreline position, sediment grain size, and foreshore beach 

slope. These variables, in addition to hydrodynamic processes, can be used to predict coastal 

vulnerability to storms. 

The U.S. Geological Survey’s (USGS) National Assessment of Coastal Change Hazards Project 

(http://coastal.er.usgs.gov/hurricanes), strives to provide hazard information to those interested in the 

Nation’s coastlines, including residents of coastal areas, government agencies responsible for coastal 

management, and coastal researchers. As part of the National Assessment, observations were collected 

to measure coastal changes associated with Hurricane Ike, which made landfall near Galveston, Texas, 

on September 13, 2008. Methods of observation included aerial photography and airborne topographic 

surveys. This report documents these data-collection efforts and presents qualitative and quantitative 

descriptions of hurricane-induced changes to the shoreline, beaches, dunes, and infrastructure in the 

region that was heavily impacted by Hurricane Ike. 

The contents of this report are divided into the following sections: 

 Section 2, Storm Overview - presents a synopsis of the storm, including meteorological 

evolution, wind speed impact area, wind-wave generation, and storm-surge extent and 

magnitudes. 

 Section 3, Coastal-Change Observations - describes the observation missions that responded to 

Hurricane Ike, which included acquisition of oblique aerial photography and airborne 

topography surveys using lidar. 

 Section 4, Coastal-Change Analysis - describes data-analysis methods and results. 

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2. Storm Overview 

2.1 Storm History 

According to the National Oceanic and Atmospheric Administration (NOAA) National 

Hurricane Center’s best track, Hurricane Ike was an active tropical-weather system in the Caribbean Sea 

and Gulf of Mexico from August 28 to September 13, 2008 (fig. 1; Berg, 2009). On September 1 at 

0600 Universal Time Coordinated (UTC), a tropical wave 1,250 km west of the Cape Verde Islands was 

identified as a tropical depression. At 1200 UTC the same day, Tropical Storm Ike became the ninth 

named storm of the 2008 hurricane season. By 0600 UTC on September 4, Ike had intensified to a 

category 4 storm with winds of 231 km/hr. Hurricane Ike passed over Grand Turk, Salt Cay, and South 

Caicos islands on September 7 and made another landfall later that day on Great Inagua Island in the 

southern Bahamas. Subsequent landfalls occurred near Cabo Lucrecia, Cuba, on September 8 and near 

San Cristobal, Cuba, on September 9 before the storm entered the Gulf of Mexico. Hurricane Ike 

crossed the Gulf of Mexico and made landfall along the north end of Galveston Island, Texas, as a 

strong category 2 storm with maximum sustained winds of 175 km/hr at 0700 UTC on September 13 

(Berg, 2009). 

Figure 1. Track of Hurricane Ike in the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. Hurricane track 

information was obtained from the National Hurricane Center (Berg, 2009). 

2.2 Extent of Hurricane-Force Winds 

Maximum sustained wind swaths estimated by the NOAA Atlantic Oceanographic and 

Meteorological Laboratory Hurricane Research Division (using methods described by Powell and 

others, 1998) indicate that hurricane-force winds impacted approximately 180 km of coastline (Fig. 2). 

The maximum wind-speeds were observed just east of Galveston, Texas. Hurricane-force winds 

extended across the Texas-Louisiana border and affected much of the Louisiana coast. 

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20

40

60

80

100

120

140

160

25

27

29

31

33

20

40

60

80

100

120

140

160

0 0.002 0

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1 Wind Speed (km/hr)

Galveston, TX

3 3o N

3 1o N

2 9o N

2 7o N

2 5o N

9 6o W 9 4o

 W 9 2o

 W 9 0o 9 8o

 W W

Figure 2. Wind speeds in kilometers per hour generated by Hurricane Ike, as calculated by the National Oceanic 

and Atmospheric Administration Hurricane Research Division. The extent of hurricane-force wind, as defined 

by a category 1 wind speed of 119 km/hr, is indicated by the orange contour. 

2.3 Offshore Wave Climate 

Several moored buoys operated by the NOAA National Data Buoy Center recorded heights and 

periods of waves generated by Hurricane Ike. Approximately 33 hrs prior to landfall, Hurricane Ike 

passed within 28 km of Buoy 42001 (fig. 1), which is located in the Gulf of Mexico approximately 330 

km south of Southwest Pass, Louisiana. The maximum significant wave height recorded at this station 

was 9.2 m (National Data Buoy Center, 2008). Buoy 42035 (fig. 1), moored east of Galveston, Texas, 

in 13.7 m of water, went adrift on September 12 and later passed through the eye of Hurricane Ike. The 

buoy recorded a maximum significant wave height of 6.0 m at 0400 UTC on September 13 (fig. 3), 3 

hrs before Hurricane Ike came ashore in Galveston, Texas (National Data Buoy Center, 2008). 

3 
9/12/08 9/12/08 9/13/08 9/13/08 9/14/08 

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0 Wave height, in meters 0000 UTC 1200 UTC 0000 UTC 1200 UTC 0000 UTC

 

 

 

 

 

 

Figure 3. Significant wave height during the passage of Hurricane Ike, as measured from National Oceanic and 

Atmospheric Administration Buoy 42035 located near Galveston, Texas. 

2.4 Storm Surge 

Measurements of maximum storm surge are generally gathered from coastal tide gages and landbased storm sensors (East and others, 2008), and high-water marks (McGee and others, 2006). During 

Hurricane Ike, many tide gages were operational, and the data have been published by NOAA (Berg, 

2009; National Weather Service Houston/Galveston, 2008). Higher-than-normal water levels affected 

all Gulf Coast States as Hurricane Ike moved into the Gulf of Mexico. The large wind field pushed 

water toward the coastline well before landfall. Maximum storm tides ranged from 0.37 to 0.87 m above 

normal along the west coast of Florida. The coasts of Alabama, Mississippi, and southeastern Louisiana 

experienced maximum storm surges ranging from 0.79 m at Gulfport, Mississippi, to 1.98 m at Shell 

Beach near New Orleans, Louisiana. West of Grand Isle, Louisiana, storm-surge heights rose 

progressively, increasing from 1.17 m at Grand Isle to 3.82 m at Port Arthur, Texas. Near landfall, 

many tide gages failed due to large wave action that destroyed the instrument platforms. On the Bolivar 

Peninsula, high-water marks indicate that all of the area was covered by at least 1 m of water with many 

areas covered by at least 3 m of water (Berg, 2009). Storm-surge levels on Galveston Island are 

estimated to have been between 3 and 4.5 m from high-water marks and the Eagle Point tide gage, 

located in Galveston Bay. South of Galveston Island along the Texas coast in Brazoria County, surge 

levels of 1.5 to 3 m were recorded. 

4 
 

 

 

 

 

 

3. USGS Coastal-Change Observations 

The USGS National Assessment of Coastal Change Hazards Project responded to Hurricane Ike 

with the following observation missions: 

 Pre-storm oblique aerial photography (completed September 10, 2008) 

 Post-storm oblique aerial photography (completed September 15, 2008) 

 Post-storm airborne lidar topographic survey (completed September 18, 2008) 

 Ground-based control surveys (completed September 18, 2008) 

The near-real-time response of this effort is documented at http://coastal.er.usgs.gov/hurricanes/ike/. 

Photographs taken after the storm are matched to pre-storm images to locate areas of extreme 

erosion and accretion, retreat of the shoreline, and damage to infrastructure. In some areas of special 

concern, repeat photography surveys are flown, allowing a closer look at the gradual recovery of the 

beach system. Additionally, aerial photographs are often valuable for the identification of buildings and 

vegetation that are not easily distinguished in lidar maps. Post-storm photos are used to plan lidar 

mapping missions to target areas with significant coastal change. The post-storm topographic-lidar 

survey targets the region that was heavily affected by the storm. The updated topography from this 

mission can be compared to pre-storm topography to estimate changes in shoreline position, dune 

elevation, and infrastructure. The post-storm topography also serves as an update for emergency and 

coastal managers who require detailed knowledge of the post-storm landscape. 

3.1 Oblique Aerial Photography and Video Observations 

The USGS oblique digital photography is collected prior to hurricane landfall and immediately 

after landfall. Pre-storm photography is conducted well before landfall or immediately prior to landfall 

if prior imagery does not exist or is excessively out of date. Digital photography is shot by hand while 

video is recorded continuously. Images are geolocated using accurate Global Positioning System (GPS) 

positions which are recorded separately and merged with the imagery in post-processing. The compact 

digital video/digital photo system (fig. 4) can be used on various aircraft such as the NOAA Twin Otter, 

the Coast Guard H60 and H65 helicopters, and commercial King Air and Navajo Chieftain aircraft. 

A pre-storm oblique aerial-photography survey of the Texas coastline was collected on 

September 9, 2008, four days before landfall, in a cooperative agreement between Louisiana State 

University, the University of New Orleans, and the USGS. The aircraft was a single-engine Cessna. In 

total, 1,767 digital photos were obtained over a 630-km extent from Cameron, Louisiana, to Port Isabel, 

Texas. 

Post-storm oblique aerial photography and video of the region of landfall were collected from a 

twin engine King Air aircraft on September 14 and 15, 2008, two days after landfall. In total, 2,521 

digital photographs and 8 hrs of video were obtained over a 240-km extent from Freeport, Texas, to 

Cameron, Louisiana. The photography sample rate was 0.5 frames/sec (or approximately 1 photo per 

200 m). Examples of both pre- and post-storm photographs obtained during these two flights are shown 

in Section 4.1. 

5 
 

 

Figure 4. Digital-photography and video recording system used aboard aircraft during coastal oblique video and 

photography missions. 

3.2 Lidar Topographic Surveys 

Modern, high-resolution lidar systems can map hundreds of kilometers of coast in a day with 

point densities exceeding one point per square meter. High point densities combined with reasonable 

horizontal and vertical accuracies allow for the creation of topographic/bathymetric digital-elevation 

models (DEM) that show details of the coastal environment. Lidar systems emit pulses of light that 

reflect off the Earth’s surface, allowing the computation of elevation from the two-way transmission 

time. The high-frequency pulses are emitted from a laser that is mounted on a small aircraft. Aircraft 

movement is monitored by an inertial navigation unit, a GPS unit, and tilt sensors. More complete 

descriptions of coastal lidar instruments and methods can be found in Brock and others (2002). 

Lidar surveys receive positioning control using differential GPS that requires a base-station 

receiver on the ground. The USGS sets up base stations near the area of hurricane impact if 

continuously operating reference stations (CORS) are not available. Additionally, because slowly 

varying positioning errors can corrupt the data (Sallenger and others, 2003), control points are surveyed 

6 
 

 

 

for use in identifying these errors. Control points on surfaces that do not vary, such as roads or parking 

lots, can be obtained using ground-based surveying methods or by utilizing previous lidar surveys. 

Ground-based surveys performed on the beach surface are required to be synchronous with the lidar 

survey because of the likelihood for rapid and significant changes associated with the storm and the 

post-storm recovery period. Vertical accuracy of the lidar survey data is expected to be on the order of 

10-20 cm (Sallenger and others, 2003), whereas the horizontal-position accuracy is on the order of 1 m 

(Nayegandhi and others, in press). 

After collection, the lidar data are processed using software specific to the lidar instrument. 

Included in the processing steps are removal of wild points and separation of points into first- and lastreturn lidar products (Bonisteel and others, in press). The lidar first- and last-returns are the first and last 

backscatter to return to the sensor from the laser pulse. First-returns can be used to estimate canopy 

height in vegetated areas or rooftop height in developed areas, while last-returns can be used to estimate 

elevation of the bare-Earth surface under vegetation. 

3.2.1 Lidar Flight Information 

An airborne lidar survey of post-storm topography was completed September 17, 2008, four 

days after landfall, on the Texas coast between Port Lavaca and Port Arthur using the USGS 

Experimental Advanced Airborne Research Lidar (EAARL) system. The EAARL system was mounted 

on a twin-engine Cessna 310 aircraft. The survey covered 300 km of coastline in 6.15 hrs and collected 

53.5 million points. Eight flight passes were flown from San Luis Pass north to Port Arthur (fig. 5), 

while only two passes were flown from San Luis Pass south to Port Lavaca. Each pass overlaps the 

adjacent pass by 30-50 percent. Lidar data were only collected for September 17, 2008. Problems with 

the laser on September 18 limited the mission to imagery only. 

3.2.2 Lidar Control GPS Base-Stations 

Ground-based survey systems were set up near the airport at Port Lavaca, TX (KPKV) and on 

the Bolivar Peninsula (KGLS) (fig. 5). New control points were created for both survey locations. 

Instrumentation details and precise locations, including ellipsoidal height, for each station are listed in 

table 1. In standby, when the lidar aircraft was not deployed, both GPS systems collected 30 sec data 

from 2008-09-17 16:28:14 to 2008-09-18 20:52:54. During flights, the sample rate was increased to 2 

Hz. GPS quality was good for both stations. 

Table 1. Details of the two GPS control stations used during the September 17-18, 2008, EAARL lidar mission. 

Station ID KPKV KGLS 

Latitude 28° 39.1288' N 29° 21.7366' N 

Longitude 96° 40.9334' W 94° 46.6855' W 

Ellipsoidal Height (WGS84) -17.521 m -24.6750 m 

Receiver Type Ashtech Z Eurocard Ashtech Z Eurocard 

Antenna Type ASH700936B_M ASH700936A_M 

7 
 

 

 

Figure 5. Hurricane Ike pre- and post-storm oblique aerial photography and video flights and post-storm lidar 

coverage. The locations of the GPS base stations are noted as black triangles. 

3.2.3 Lidar Quality 

First-return lidar points were interpolated to a series of regular 5 x 5 m grid domains. The 

interpolation method applies a smoothing filter that removes short-scale variability and determines the 

degree to which residual noise has been removed. Elevations at grid points that received too few 

observations to reduce system noise were removed. Evaluation of the actual vertical accuracy of the 

8 
 

 

lidar could not be performed against ground-based surveying because the lidar flight path did not 

overlap the ground base station. Since no ground surveys were conducted concurrent with the 

September 17, 2008, lidar survey, a relative offset between the 2005 and 2008 data was determined. 

Lidar data were selected from a number of small areas containing fixed, flat features, such as roads, 

parking lots, and large buildings (fig. 6). For this intercomparison, a section of the city of Galveston was 

used. Grid cells were then selected based on their spatial error (normalized sampling error less than 25 

percent and residual error less than 20 cm) to eliminate cells with a small number of observations or 

high noise due to system behavior, or vegetation, or other sources of clutter. The grid cells that were 

selected were used to determine the relative offset of + 32 (+/- 0.001) cm (fig. 7), indicating that the 

2008 survey was biased high compared to the 2005 survey. This bias may be due to navigation errors in 

either or both of the surveys used in the comparison. Since the bias is within the vertical-error limits of 

the lidar surveys (+/- 20 cm), the bias has not been removed from either dataset. The presence of a bias 

is important because it increases the uncertainty of the measures of coastal change presented in Section 

 95o10' W 95o00' W 94o50' W 94o40' W 94o30' W 

 29o00' N 

 29o06' N 

 29o12' N 

 29o18' N 

 29o24' N 

 29o30' N 

Gulf of

Mexico

Galveston

Bay

Area selected for 2005,

2008 lidar survey

relative offset

evaluation

4.2. 

Figure 6. Map of Galveston Island. Red square shows location of the area selected for evaluating the relative 

offset between 2005 and 2008 lidar surveys. 

9 
 

 

 

 

 

Figure 7. Relative offset between 2005 and 2008 Experimental Advanced Airborne Research Lidar first-return 

lidar. 

4. Coastal-Change Analysis 

The pre- and post-storm photography and the pre- and post-storm lidar topography were 

compared to describe and quantify the spatial extent, nature, and magnitude of coastal changes. The 

photography was used to identify examples of coastal changes that span the range of responses to the 

hurricane conditions. The lidar topography quantifies these changes. The quantitative analyses include 

estimates of changes in dune height, shoreline position, and sediment volume. 

4.1 Photo Comparison Analysis 

4.1.1 Surfside Beach to San Luis Pass, Texas 

On the sandy beaches west of Galveston Island (fig. 8, locations 1 and 2), peak dune elevations 

before the storm ranged from 2 to 4 m. The coastal change along this largely undeveloped stretch of 

beach was less severe than the change observed on Galveston Island and Bolivar Peninsula. Large 

waves and surge eroded the beach, causing shoreline retreat and scarping of the dune face (figs. 9 and 

10). 

10 
 95o00' W 94o30' W 94o00' W 9 3o30' W

 28o40' N 

 29o00' N 

2 9o20' N

 29o40' N 

 30o00' N 

Calcasieu 

Sabine Lake 

 Lake

Houston

Galveston 

Bay

2

3

4

5

6

7

8

9

10

11

12 13

Gulf of Mexico

1

Cameron

 Parish

High Island

 to Sabine Pass

Bolivar 

Peninsula

Galveston

Surfside Beach

 to San Luis Pass

Figure 8. Location index for photo pairs (Figures 9-21) from Surfside Beach, Texas to Cameron Parish, 

Louisiana. 

11
 
 

 

Figure 9. Oblique aerial photography from Quintana, Texas (Location 1, Figure 8) on September 9, 2008 (top) 

and September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark features visible 

in each image. At this location well west of Ike's landfall location, there is evidence of erosion of the seaward 

leg of the rectangular berm. The steep scarp is typical of erosion due to wave collision against the berm slope. 

Erosion and overwash can be seen on the lower dune to the west (left) of the larger berm. 

12 
Figure 10. Oblique aerial photography from Christmas Bay, Texas (Location 2, Figure 8), on September 9, 2008 

(top), and September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark features 

visible in each image. Here, severe beach and dune erosion occurred, and overwash or inundation deposited 

sand behind remnants of the dune and onto the road. 

13 
 

 

 

 

 

 

 

4.1.2 Galveston, Texas 

Most of Galveston Island was west of Hurricane Ike landfall (fig. 8, locations 3-5) and was not 

exposed to the extreme winds of the right eyewall that devastated the Bolivar Peninsula. On the sandy 

beaches west of the Galveston seawall, peak dune elevations before the storm were 2 to 4 m, roughly 

half of the elevation of the seawall. The coastal change along this stretch of Galveston Island was 

considerably more than on the seawalled section nearby, but less than the change observed on the 

Bolivar Peninsula. At landfall, while the Bolivar Peninsula was being pummeled with extreme onshore 

winds, much of Galveston Island experienced offshore winds, reducing both surge and, to some extent, 

wave heights. However, impacts were not absent. Waves, aided by high surge, eroded the beach, 

moving the shoreline landward of some houses west of the seawall (fig. 11). 

The city of Galveston was protected from storm surge and wave attack by a 5- to 6-m high, 16­

km-long seawall. Erosion was restricted to the beach in front of the seawall (fig. 12). Here, most of the 

severe impacts to buildings were confined to those that were built on piers that extended seaward of the 

seawall. A small section of the eastern end of the island was not protected by the seawall. This area was 

on the right-hand side of the hurricane track and likely experienced the strongest winds, and the highest 

surge and waves, leading to beach and dune erosion (fig. 13). 

14 
 

Figure 11. Oblique aerial photography of Galveston, Texas (Location 3, Figure 8), on September 9, 2008 (top), 

and September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark features visible 

in each image. Evidence of inundation here includes eroded beach face, sand deposited inland of the 

shoreline, and distressed vegetation. However, the coastal-change impacts were less severe here than on the 

Bolivar Peninsula, located northeast of landfall. 

15 
 

 

Figure 12. Oblique aerial photography of Galveston, Texas (Location 4, Figure 8), on September 9, 2008 (top) and 

September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark features visible in 

each image. Hurricane-induced waves and surge destroyed a pier and eroded adjacent beaches. 

16 
 

 

Figure 13. Oblique aerial photography of Galveston, Texas (Location 5, Figure 8), on September 9, 2008 (top) and 

September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark features visible in 

each image. Hurricane-induced waves and surge destroyed a small walkway. Coastal-change impacts include 

beach and dune erosion, and the removal of considerable dune vegetation. This location is on the right-hand 

side of the hurricane track and likely experienced the strongest winds, highest surge, and waves. 

17 
 

 

 

4.1.3 Bolivar Peninsula 

Hurricane Ike made landfall at the mouth of Galveston Bay, thus exposing the coast lying east of 

landfall to the right-front quadrant of the storm, the location of the strongest winds. The storm surge, 

onshore-directed winds, and waves all focused their greatest energy in this area. The combination of low 

dunes and high-surge levels on the Bolivar Peninsula (fig. 8, locations 6 and 7) made those beaches 

vulnerable to inundation and large-scale coastal changes during landfall. Entire neighborhoods were 

destroyed by battering waves riding on top of a 5-m storm surge. Low sand dunes (about 2 m elevation) 

protecting beach-front neighborhoods were flattened by erosion, and sand from the beach and dunes was 

transported landward and ultimately deposited across the width of several blocks (figs. 14 and 15). At 

the narrowest part of the Peninsula near Gilchrist, Texas, the sand and debris were swept into Galveston 

Bay. 

18 
 

 

Figure 14. Oblique aerial photography of Bolivar Peninsula, Texas (Location 6, Figure 8), on September 9, 2008 

(top) and September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark features 

visible in each image. In addition to loss of houses, the evidence of inundation here includes eroded dune face 

and sand deposited well inland of the shoreline. 

19 
 

 

Figure 15. Oblique aerial photography of Bolivar Peninsula, Texas (Location 7, Figure 8), on September 9, 2008 

(top), and September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark features 

visible in each image. In addition to the loss of houses, the evidence of inundation here includes eroded dune 

face and sand deposited well inland of the shoreline. 

20 
 

 

 

4.1.4 High Island to Sabine Pass, Texas 

Farther east across the upper Texas coast (fig. 8, locations 8-10), the pre-storm morphology was 

different and so were the impacts. Before the storm, dune elevations (or berms in the absence of dunes) 

were extremely low, ranging from only 1 to 2 m high. Landward of mainland beaches were low-lying 

marshlands. The storm surge of 3 to 4 m overtopped the beach systems and, in places, inundated the 

marshes tens of kilometers landward from the shoreline. Two days after the storm, floodwaters were 

still present, held in place by what remained of the beaches that acted like levees containing the water 

(figs. 16 and 17). The beach crests rose above the water and resembled barrier islands, whereas they 

were actually mainland beaches. Breaches were cut through these 'barriers' and water flowed seaward, 

slowly draining the huge, shallow lakes. During this process, eroded sand was transported seaward into 

the Gulf of Mexico (fig. 18). 

21 
 

 

Figure 16. Oblique aerial photography near McFaddin Wildlife Refuge, Texas (Location 8, Figure 8), on September 

9, 2008 (top) and September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark 

features visible in each image. Widespread inundation and persistent flooding are obvious but the extent of 

coastal change is difficult to assess. 

22 
 

 

Figure 17. Oblique aerial photography near McFaddin Wildlife Refuge, Texas (Location 9, Figure 8), on September 

9, 2008 (top) and September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark 

features visible in each image. Again, widespread inundation and persistent flooding are obvious. The white 

foam at the bottom of the post-storm photo is due to the return flow cascading over the berm as the area drains 

into the Gulf of Mexico. 

23 
 

 

 

Figure 18. Oblique aerial photography near McFaddin Wildlife Refuge, Texas (Location 10, Figure 8), on 

September 9, 2008 (top) and September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow 

arrows mark features visible in each image. Evidence of widespread inundation is apparent. The flooded area 

continues to drain through a channel that cuts through the roadway. The dunes have been eroded and 

dissected. Backflow through this area transported sediment offshore. 

24 
 

 

 

4.1.5 Cameron Parish, Western Louisiana 

The morphology of the western Louisiana coast (fig. 8, locations 11-13) is similar to that of the 

Texas coastline north of the Bolivar Peninsula. Before the storm, dune elevations (or berms in the 

absence of dunes) were low, ranging from only 1 to 2 m high. Landward of the beaches were low-lying 

marshlands. The storm surge of 1 to 3 m overtopped the beach systems in many areas, and waves (figs. 

19 and 20) eroded the shoreline landward. The town of Holly Beach, Louisiana, which was completely 

destroyed by Hurricane Rita in 2005, was once again flooded by Hurricane Ike (fig. 21). 

25 
 

 

Figure 19. Oblique aerial photography from Cameron Parish, Louisiana (Location 11, Figure 8), on September 9, 

2008 (top) and September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark 

features visible in each image. Widespread inundation and persistent flooding are obvious. Coastal change 

includes both beach erosion and erosion of channels where water continues to flow seaward to the Gulf of 

Mexico. 

26 
 

Figure 20. Oblique aerial photography from Peveto Beach, Louisiana (Location 12, Figure 8), on September 9, 

2008 (top) and September 15, 2008, two days after landfall of Hurricane Ike (bottom). Yellow arrows mark 

features visible in each image. Evidence of widespread inundation includes erosion of the berm and channels 

that drained the flooded area. 

27 
 

 

 

 

 

Figure 21. Oblique aerial photography from Holly Beach, Louisiana (Location 13, Figure 8), from 2001-2008. 

Yellow arrows mark features visible in each image. The first photo shows this area prior to landfall of Hurricane 

Rita on September 24, 2005. Immediately after Rita's landfall, the September 28, 2005, photo shows 

destruction of houses. Prior to Ike's landfall, on September 9, 2008 there is little evidence of a dune or berm on 

this beach. Several houses and smaller structures have been rebuilt. On September 15, 2008, two days after 

landfall of Hurricane Ike, the beach is eroded and there is evidence of overwash and persistent flooding. 

4.2 Quantitative Topographic-Change Analysis 

Last-return lidar data were analyzed to compare morphologic changes due to Hurricane Ike. The 

morphologic analysis was optimized for identifying shorelines and dune height. The analysis required 

interpolation to a gridded domain that was rotated parallel to the shoreline and had a resolution of 10 m 

in the longshore direction and 2.5 m in the cross-shore direction. The interpolation method applies 

spatial filtering with a Hanning window that is twice as wide as the grid resolution (Plant and others, 

2002). Grids of pre- and post-storm lidar topography can be differenced over the entire overlapping 

survey area to compute elevation or volume changes over various distances and to give a quick visual of 

coastal change. For the town of Crystal Beach, Texas, on the Bolivar Peninsula, difference grids reveal 

loss of homes, erosion of the shoreline, and reduction of dune elevations (figs. 22-24). Overwash 

deposits (fig. 24) can be seen several hundred meters from the shoreline. 

28 
Figure 22. September 2005 Experimental Advanced Airborne Research Lidar first-return lidar digital elevation 

model of Crystal Beach, Texas. 

29
 
Figure 23. September 2008 Experimental Advanced Airborne Research Lidar first-return lidar digital elevation 

model of Crystal Beach, Texas. 

30
 
 

 

Figure 24. Coastal Change at Crystal Beach, Texas, due to Hurricane Ike. The coastal change between the two 

dates is determined from the difference between the two datasets. For the coastal-change figure, red indicates 

at least 1 m of erosion and blue indicates at least 1 m of deposition. The spatial coverage of the two data sets 

differs and the 2008 mission had more extensive coverage than the 2005 mission in this area. 

4.2.1 Dune Elevation Change 

Gridded lidar data were used to estimate changes in elevation and position of the frontal sand 

dune or berm system (Stockdon and others, in press). Dune or berm-elevation change is calculated as 

the difference between elevation of the pre-storm dune crest (September 2005) and the post-storm 

elevation (September 2008) (fig. 25A). The elevation change is estimated at the location of the prestorm dune crest. 

Extreme elevation changes of about 3 m were observed near Crystal Beach, Texas, which is 

located on the Bolivar Peninsula and was in the right-front quadrant of the hurricane impact zone. 

Dune-height changes exceeding 1 m were observed more than 60 km to the right of the landfall position. 

31 
 

 

 

 

Dune-height changes exceeding 1 m were observed as far as 40 km to the left of landfall. In Galveston, 

Texas, the seawall is considered to be the dune crest and the elevation change is roughly 30 cm, 

consistent with the previously determined vertical offset. 

4.2.2 Shoreline Change 

From each row of the shore-parallel-oriented grids, the cross-shore position of the datum-based 

shoreline was extracted (Stockdon and others, 2002). The shoreline vertical datum was defined to be 

0.37 m above mean sea level, based on NAVD88 vertical datum and GEOID96 model. These shoreline 

positions are compared to shorelines from the pre-storm survey, providing a quantitative description of 

shoreline change. Shoreline change is calculated as the difference between the pre-storm shoreline 

(September 2005) and the post-storm shoreline from the EAARL survey of September 17, 2008 (fig. 

25B). Uncertainties in shoreline position vary due to data noise and beach slope, but typical errors in 

shoreline position are on the order of 1-2 m (Stockdon and others, 2002). Because the surveys span 3 

years, the shoreline change can be both storm-induced short-term and background long-term change. 

Shoreline erosion of 150 m was observed near Gilchrist, Texas. More than 50 m of shoreline 

erosion was experienced over a wide region from the seawall extending 15 km to the west. The area of 

positive shoreline change at the south end of Galveston Island is related to spit formation at San Luis 

Pass and may not be related to Hurricane Ike. The area of positive shoreline change 80 km to the right 

of landfall is due to the seaward transport of sediment as storm water drained from the marshes (fig. 18). 

4.2.3 Beach-Volume Change 

Volume-change calculations were performed by contouring the topography at a fixed vertical 

datum, which was set at mean high water from tidal records (Weber and others, 2005). The volume is 

calculated between the cross-shore location of the pre-storm dune base and the pre-storm shoreline. 

This eliminates complications from structures and vegetation, which generally are located landward of 

the dune base. Beach volume change was calculated as the difference between the September 2005 and 

September 2008 surveys (fig. 25C). 

Volume losses typically follow the same pattern as the shoreline changes in the region to the 

west of Galveston. This implies that sediment lost due to erosion was not deposited farther landward. 

East of landfall, volume changes were highly variable. Some areas, such as the region between Crystal 

Beach and Gilchrist, Texas, experienced substantial volume loss. However, the town of Crystal Beach, 

Texas, experienced little net sediment loss. This is consistent with the appearance of overwash deposits 

that presumably contain the sediment that was eroded from the shoreline and dunes (fig. 24). The 

positive volume change near the San Luis Pass at the south end of Galveston Island is likely long-term 

sediment accumulation at the inlet. Volume change along the seawall of Galveston is positive due to the 

30-cm relative offset. 

32 
 

 

Figure 25. Hurricane Ike (A) dune-elevation change (B) shoreline change (C) and beach-volume change. Blue 

lines indicate the center of the towns of Galveston, Crystal Beach, and Gilchrist, Texas. 

5. Acknowledgments 

The USGS National Assessment of Coastal Change Hazards Project thanks the many scientists 

and support staff who invested long hours during the 2008 hurricane season. Specifically, we thank the 

EAARL research team (Wayne Wright and Richard Mitchell) and ground surveyor (B.J. Reynolds). 

Colleagues at the University of New Orleans conducted the pre-storm photography mission (Karen 

Westphal); colleagues in the St. Petersburg office helped with data collection (Dennis Krohn, Karen 

Morgan, and Kristy Guy), processing and analysis (Charlene Sullivan, Peter Howd, Mark Hansen, Dave 

Thompson, and Ann Marie Ascough), and web page development (Jolene Shirley). 

33 
 

 

 

 

 

References Cited 

Berg, R., 2009, Tropical cyclone report Hurricane Ike: National Oceanic and Atmospheric 

Administration National Hurricane Center Report AL092008, 55 p. 

Bonisteel, J., Nayegandhi, A., Brock, J.C., Wright, C.W., and Nagle, D.B., in press, Experimental 

Advanced Airborne Research Lidar (EAARL) data processing manual: U.S. Geological Survey OpenFile Report 0000-0000. 

Brock, J.C., Wright, C.W., Sallenger, A., Krabill, W., and Swift, R., 2002, Basis and methods of NASA 

airborne topographic mapper lidar surveys for coastal studies: Journal of Coastal Research, vol. 18, 

no. 1, p. 1-13. 

East, J.W., Turco, M.J., and Mason, R.R., Jr., 2008, Monitoring inland storm surge flooding from 

Hurricane Ike in Texas and Louisiana, September 2008: U.S. Geological Survey Open-File Report 

2008-1365. 

McGee, B.D., Goree, B.B., Tollett, R.W., Woodward, B.K., and Kress, W.H., 2006, Hurricane Rita 

surge data, southwestern Louisiana and southeastern Texas, September to November 2005: U.S. 

Geological Survey Data Series 220. 

National Data Buoy Center, 2008, Reports from the National Data Buoy Center's stations during the 

passage of Hurricane Ike: National Oceanic and Atmospheric Administration, Accessed at 

http://www.ndbc.noaa.gov/hurricanes/2008/ike on February 10, 2009. 

National Weather Service, 2008, Hurricane Ike storm surge estimates from damage surveys: National 

Oceanic and Atmospheric Administration, Accessed at 

http://www.srh.noaa.gov/hgx/projects/ike08/storm_surge_overview.htm on December 3, 2008. 

Nayegandhi, A., Brock, J.C., and Wright, C.W., in press, Small-footprint, waveform-resolving lidar 

estimation of submerged and sub-canopy topography in coastal environments: International Journal of 

Remote Sensing. 

Plant, N.G., Holland, K.T. and Puleo, J.A., 2002. Analysis of the scale of errors in nearshore 

bathymetric data: Marine Geology, vol. 191, p. 71-86. 

Powell, M.D., Houston, S.H., Amat, L.R., and Morisseau-Leroy, N., 1998, The HRD real-time 

hurricane wind analysis system: Journal of Wind Engineering and Industrial Aerodynamics, vol. 77­

78, p. 53-64. 

Sallenger, A., Krabill, W.B., Swift, R.N., Brock, J., List, J., Hansen, M., Holman, R.A., Manizade, S., 

Sontag, J., Meredith, A., Morgan, K., Yunkel, J., Frederick, E., and Stockdon, H., 2003, Evaluation 

of airborne topographic lidar for quantifying beach changes: Journal of Coastal Research, vol. 19 , no. 

1, p. 125-133. 

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Stockdon, H., Sallenger, A., List, J., and Holman, R., 2002, Estimation of shoreline position and change 

using airborne topographic lidar data: Journal of Coastal Research, vol. 18, no. 3, p. 502-513. 

Stockdon, H.F., Doran, K.S., and Sallenger, A.H., in press, Extraction of lidar-based dune-crest 

elevations for use in examining the vulnerability of beaches to inundation during hurricanes: Journal 

of Coastal Research Special Issue. 

Weber, K.M., List, J.H., and Morgan, K.L.M., 2005, An operational mean high water datum for 

determination of shoreline position from topographic lidar data: U.S. Geological Survey Open-File 

Report 2005-1027. 

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