Meridian Awards 2010

Two years ago, during preparations for hurricane season, the question was raised whether there was any historic information available on past hurricanes that hit Tampa. I decided to research the “Gale of 1848”, which was the worst hurricane in recorded history to visit the Tampa Bay area. The entire west coast of Florida was destroyed by it. I found three surveys from the 1840’s and 1850’s and was able to register these images, digitize the features and ultimately overlay them on our modern GIS layers. I found dozens of historic accounts from the victims of the storm and was able to identify their home sites from the old surveys. I brought in our modern 1 ft. contour lines and was able to verify their stories about how the storm surge destroyed their houses and stores. A timeline was then built to demonstrate what approximate times each of the buildings was affected.

The storm surge in downtown Tampa was known to be 15 ft. We also have a second known surge height in Tampa Bay at the old Egmont Key lighthouse. From these two known water levels I was able to use Tampa Bay Port Authority anchorage buoy data and determine the track that storm took. No one has ever been able to do this. Historic accounts from Tampa, central Florida and the east coast of Florida also verify the storm track. I was also able to use the Fort Brooke surgeon’s barometric readings to determine the intensity of the hurricane and further verify this theory.

Knowing the track and intensity of the storm allowed me to again use the Tampa Bay Port Authority anchorage data and show what the surge heights throughout Tampa Bay would have been at the climax of the storm. I then used FME to create a storm surge polygon from contour line features. Ultimately, I brought in Tampa’s modern road and parcel layer and performed a boundary select with the surge height polygon and determined the properties as well as the miles of roads that would have been inundated by surge water. Finally I calculated the property values of the selected parcels.

Tampa has not had a direct hit from a hurricane since the 1920’s. We have to look far into our past to get an idea of what effects a severe storm would have on Tampa. MapInfo allows us to visually see what happened in the past and accurately calculate what impact an identical storm would have today.