Geology Picture of the Week, August 15-21, 2004: Tampa Bay

NASA Earth Observatory ^ | August 13, 2004 | Landsat

[cogitator]

This image seemed quite timely in the wake of Charley. Despite the magnitude of the disaster and the hardship currently being endured by Florida citizens that are affected, it could have been much, much worse if Charley had gone up through Tampa Bay the way that it went up through Charlotte Harbor. The largest city near Charlotte Harbor, Ft. Myers, isn't on Charlotte Harbor, whereas St. Petersburg and Tampa both sit right on the bay shore.

I've got some local knowledge of the area, by virtue of a friend that has a house on the Intercoastal Waterway on the western "coast" of St. Petersburg. You can actually see just about where his house is located. Central St. Petersburg is bisected by a prominent east-west set of avenues (1st Avenue South, Central Avenue, and 1st Avenue North), which provide a fairly quick route from the beaches to downtown St. Petersburg, if you're ever in the area.

Start at downtown St. Petersburg, which is on the western side of the Bay. The oblong shape is a small airport (you can see the main runway). Just north of that, projecting into the Bay, is the St. Petersburg Pier, a tourist landmark. The avenues I mentioned above are just south, lighter gray. Follow them west until they reach water, which is the Treasure Island Causeway. My friend's house is just north of the Causeway.

Now here's my interesting geological insight. If you take the causeway out to the beach (Treasure Island) and then turn north, in a short distance the beach road crosses John's Pass, to Madeira Beach. John's Pass is a hurricane-formed pass that was started as a beach overwash from a STRONG hurricane in 1848. According to little tidbits on the Web, the storm surge was 15 feet and virtually wiped out what consisted of Tampa at the time. (They've kept the pass open with periodic dredging ever since.) If a hurricane that strong hit this region again, the destructive potential is incalculable.

Below the image (which is linked to the higher-resolution version) are a couple of pages about John's Pass. The page about the image is linked above.

The Legendary History of John's Pass

Friendly Fisherman Panorama (panoramic view of John's Pass today)

[cogitator]

Here's hoping and praying that the Charley recovery goes smoothly and quickly.

[cogitator]

** ping **

[Chani]

bttt

[Defend the Second]

As a boy I lived on Coquina Key (just south of the airport you mention - called Albert Whitted Airport) and spent many, many days on Egmont Key (shaped like a backwards apostrophe) and Mullet Key (shaped like a wishbone) to the left of the Sunshine Skyway Bridge which crosses the mouth of the bay.

Egmont Key has a nineteenth century lighthouse on it that was still in use in the 60's when I camped (and was eaten by mosquitoes) there. Whenever you built a fire on the beach the lighthouse keeper would walk down and tell ghost stories to kids like us. Mullet Key has old Fort DeSoto, an 1890's vintage harbour battery designed to protect Tampa Bay from the Spanish during the Spanish-American War. In the 60's you could crawl all over 3 giant, rusted howitzers that were still in the fort. Both these places are parks now.

Both islands were used for fighter gunnery practice during WWII and as a kid you could find .50 caliber shell casings all over those islands.

Thanks for the photo. It brought back many fond memories.

[dirtboy]

Man, talk about a bay aligned to maximize storm surge.

[cogitator]

Man, talk about a bay aligned to maximize storm surge.

Charlotte Harbor has a very similar shape.

If you want to see something decidedly "uncool", yet fascinating in the sense of I-sure-hope-I'm-not-there-if-this-happens, look at this PDF:

Hurricane Storm Surge Simulations for Florida's Tampa Bay Region

Note especially Figures 3 and 17. Compare to the image provided in this thread. Take a deep breath. You'll need it.