Tybee Island
About Tybee Island |
Storm Surge History |
The Tybee Island area was inhabited by Native Americans for thousands of years, with Tybee being the Native word for "salt". Modern-day Tybee Island has a population of approximately 3,100 people (2017 Census), but is less than 20 miles from Savannah, creating a popular tourist destination. The lighthouse on Tybee Island is one of the few remaining 18th century lighthouses still operational in North America, first built in 1736. Fort Pulaski on Tybee Island is a Civil War National Monument landmark site, where the important use of rifled cannons changed how masonry fortifications were used. Because of its ideal location to the Savannah River, Tybee Island beaches are popular for its warm weather and cool breezes.
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U-Surge provides high water marks from 59 hurricanes and tropical storms at Tybee Island since 1890. Hurricane Frederic (1979) generated the highest storm tide on record, as the water level reached 12 ft above the Annually-Adjusted MSL (AAMSL). Hurricane Ivan's (2004) 11.41-ft storm tide reached second place; this destructive flood event remains fresh in the local memory. Two major floods in the early 1900s impacted Pensacola- an unnamed hurricane in 1906 generated a storm tide 10 ft and the Great Miami Hurricane of 1926 redeveloped in the Gulf and pushed a 9.41-ft storm tide at Pensacola. These four hurricanes generated water levels substantially higher than other events on record and they all occurred in September.
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Infographics
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Histogram
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Time Series
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Most Severe Surges
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This histogram provides the maximum water levels of the 59 recorded storm tide events at Pensacola since 1890. The events are ordered from the highest water level (Rank = 1) to lowest (Rank = 59). These events are not placed in chronological order. All data are detrended to remove the influence of relative sea level rise, so they represent water levels above an Annually-Adjusted Mean Sea Level (AAMSL).
This time series provides maximum water levels from 59 recorded storm tide events at Pensacola since 1890. These events are ordered chronologically from oldest (left) to newest (right). The numerous low-magnitude events in recent decades are influenced by both climate and data availability. All data are converted to NAVD88 datum, however, the data are intentionally not detrended, so the influence of relative sea level rise is included. SLR trend taken from NOAA tide gauge at Pensacola.
Statistics/ Return Period
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Return Period Graph
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Extreme Water Levels
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Storm tide return levels graph for Pensacola. This graph uses a log-linear regression plot based on observed data from 1890-2018 (129 years). The graph uses the Weiboll Plotting Position Formula, whereby the probability of an extreme event occurring is Rank/ (n+1), where "n" is the number of years in the data record. These data have been detrended to remove the influence of sea level rise and all data are plotted relative to Annually Adjusted Mean Sea Level (AAMSL). The regression line represents the line of best fit and indicates return levels (y-axis) for various return periods (x-axis).
Return Period |
Storm Tide Level (Feet above AAMSL) |
500-year |
12.63 |
200-year |
10.77 |
100-year |
9.37 |
50-year |
7.97 |
25-year |
6.57 |
10-year |
4.71 |
Extreme water levels above Annually-Adjusted Mean Sea Level (AAMSL) with long-term sea level rise removed. The correct way to interpret these levels is as follows: Based on a log-linear regression of observed data from 1890-2018, storm tide levels at Pensacola should equal or exceed 9.37 ft every 100 years, on average, above the annually-adjusted MSL. According to the regression equation, the 1906 Hurricane's 9.97-ft storm tide was a 135-year event and Hurricane Ivan's (2004) 9.71-foot storm tide was a 118-year event.
Sea Level Rise and Future Extreme Water Levels
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Past SLR Graph
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Future SLR Graph
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Future SLR Table
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Future Extreme Water Levels
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Future Extreme Water Levels Graph
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Year |
100-Year Flood Intermediate SLR |
100-Year Flood Intermediate-High SLR |
2000 |
9.73 |
9.73 |
2020 |
10.19 |
10.32 |
2040 |
10.71 |
11.04 |
2060 |
11.44 |
12.19 |
2080 |
12.32 |
13.63 |
2100 |
13.37 |
15.57 |
This table provides future 100-year water levels above NAVD88 datum. These numbers are calculated by adding four values: 1) The 100-year storm tide listed in the Statistics/ Return Period section- measured in feet above AAMSL; 2) An adjustment from MSL to NAVD88, which involved adding 0.30 ft to all water levels for Pensacola; 3) A conversion from water levels in 1992 (the mean year of the Present Epoch for Pensacola tide gauge data) to 2000, based on a long-term SLR rate of 0.76 ft/ century, which meant adding 0.06 ft; 4) Sea-Level rise projections from NOAA (2017), shown in the Future SLR Graph and Table above.
Extreme water level predictions for the 100-year coastal flood event at Pensacola. All of these projected values pertain to water levels for the "100-year storm" (1% annual chance) in the future. This analysis assumes stationarity in the flood level above the Annually Adjusted Mean Sea Level (AAMSL), so the increase in values are completely due to sea-level rise. According to this graph, there is a 1% chance that water levels will equal or exceed 12.19 feet in the year 2060, according to the intermediate-high SLR projection. These values do not account for wave action in velocity zones.
Data Sources
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NOAA Tide Gauge
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Data-Selection Circle
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Tide Gauge Site: Fort Pulaski, GA 8670870
Operation: National Ocean Service (NOS) Coordinates (corrected): Lat: 32.0347, Lon: -80.9030 Coordinates (given by NOAA Tides and Currents): Lat: 32.0367 Lon: -80.9017...these plot across SC border in river 6-Min Water Level Data December 1, 1995 - Present Hourly Water Level Data July 1, 1935 - March 31, 1974 July 2, 1974 - July 31, 1974 August 1, 1975 - February 28, 2019 The NOS tide gauge at Fort Pulaski provides verified hourly data for the Savannah/Tybee Island area since 1935 and verified 6-min data since 1995. |
The data-selection circle for the Tybee Island U-Surge Project has a radius of 2.5 miles and is centered on Lat: 32.0124, Lon: -80.8743. This circle contains all of Tybee Island and the extreme eastern portion of the Savannah River, including NOAA's Fort Pulaski tide gauge, which provides high water level data since 1935.
Missing Data
We have identified five hurricanes/ tropical storms since 1900 that may have generated storm tides exceeding 4 ft (1.22 m) near Pensacola, but a literature review does not yet provide data. These maps are provided by Unisys Corporation
Storm Surge Multimedia
Note: All of these pics/ video were taken from Savannah/Tybee Island area
Hurricane Irma (2017)
Nice storm surge video at Pensacola. At 51 seconds into the video do you see evidence of a nice rip current pushing offshore? Look for elongated area of white water perpendicular to the coast. Any coastal experts want to confirm this?
Hurricane Isaac (2012)
Hurricane Katrina (2005)
Hurricane Ivan (2004)
Link: https://www.youtube.com/watch?v=o_uzqfhwc4k&t=196s. Excellent storm surge footage at several places in this video. The footage at 2:45 is amazing...shot from a parking garage in the dark. This video was the first to teach me what storm surge really looks like...I remember that I was surprised to see the waves were so low-magnitude/ high-frequency. Excellent work, Mike!
Frederic (1979)
Librarians at Pensacola Library sent this image
Unnamed (1932)
Great Miami Hurricane (1926)
Link: http://www.hurricanecity.com/images/4-1926%20hurricane.jpg
Unnamed (1906)
Pensacola Harbor in 1906. Link: https://www.floridamemory.com/items/show/38376
1888- 1898
Chart depicting the count of hurricanes and tropical storms passing within 75 nautical miles of Hilton Head, South Carolina. Note the period of hyperactive hurricane history in the late 1800s....in the 11-year period of 1888 to 1898, eight hurricanes passed in this region. Hilton Head is only 15 miles northeast of Tybee Island, so this era of active hurricane history would have impacted Tybee Island as well.