Saturday, September 1, 2012

Hurricane Isaac Preliminary Maximum Storm Surge Levels

I've comprised a list of preliminary Hurricane Isaac maximum storm surge levels, taken from NOAA Tides and Currents (National Ocean Service), USGS tide gauges, and at least one anecdotal source. This list will probably grow as more data become available. Later this fall or this winter, the list will become official, as verified surge data and published reports become available.

Rank Level_ft   Station Name State Agency/ Source Datum
1   13.6   Lake Borgne Surge Barrier LA NAT
2   11.02   Shell Beach LA NOS NAT
3   10.9   Little Irish Bayou at I-10 LA USGS NAVD88
4   8   Bayou Laloutre at Ycloskey LA USGS NAVD88
4   8   Bay Waveland Yacht Club MS NOS NAT
6   7   Pass Manchac LA USGS NAVD88
7   6.2   New Canal Station LA NOS NAT
8   6.1   Liberty Bayou at Hwy 433 LA USGS NAVD88
9   4.6   Coast Guard Sector Mobile AL NOS NAT
10   4.4   Pascagoula NOAA Lab MS NOS NAT
11   4.3   Chickasaw Creek AL NOS NAT
12   4.2   Grand Isle LA NOS NAT
13   4   Mobile Bay at Hwy 193 AL USGS NAVD88
13   4   Pilots Station East, SW Pass LA NOS NAT
15   3.55   Dauphin Island AL NOS NAT
16   3.5   Pensacola FL NOS NAT
17   2.5   Panama City FL NOS NAT
18   2.2   Lawma, Amerada Pass LA NOS NAT

Note: NOAA Tide and Currents (NOS) data are storm surge levels, or height above normal astronomical tide. USGS data are storm tide levels, measured above NAVD88 level. All data are preliminary.

How do these data fit into the larger context of storm surge history along the U.S. Gulf Coast? Are any of these surge levels unprecedented for a category-1 hurricane? How do these water levels compare to other surges in a specific location?

Although it's impossible to answer all of these questions on the surge blog, if you have specific questions like these, please contact "Hurricane" Hal Needham at Hal maintains SURGEDAT, the world's most comprehensive storm surge database. SURGEDAT has currently archived more than 6,000 coastal high water marks produced by hurricanes and tropical storms along the U.S. Gulf Coast and U.S. Atlantic Coast. SURGEDAT also contains data for more than 250 peak surge events that have occurred internationally since 1880.


  1. Hal,

    Good data. I live in Waveland and was comparing Isaac with Gustav. Looks like similar storm tide but not so storm surge. Also noticed a double peak storm tide at Bay-Waveland Yacht club. What do you make of this?

    1. Steve,

      Hey, thanks for your post. The double peak storm surge is an interesting phenomenon. Sometimes this happens if the peak storm surge lasts long enough for two high tides to occur. For example, if surge level is four feet and high tide is one foot above mean sea level, two high tides during time of peak surge would produce two five-foot storm tides.

      I've also seen this happen when the storm surge actually moves in during two separate phases. For example, during Hurricane Ike, water pushed out ahead of the storm in the form of large swells and this caused water to pile up well in advance of landfall. Then the water level lowered a bit, before a dramatic rise as the storm approached landfall. From what I've heard, the first peak surge was not nearly as high as the second, but it was high enough to inundate some evacuation routes.

      How would you say Gustav's surge was different than Isaac's at Waveland? And did the duration of Isaac's surge last a lot longer than Gustav's?