Over the years, hurricane experts and emergency managers have become more aware that the real danger from the giant storms is storm surge. Storm surge is much like a tsunami: a huge mass of water pushed that can devastate a wide area in and around the storm's immediate landfall area.
While Tampa Bay has been historically lucky when it comes to hurricane hits there's no reason to believe that lucky streak will run forever. While most of us watch the wind speeds as the main measure of a hurricane's strength, storm surge can be a deadly part of relatively weaker tropical storms or hurricanes. ("Relatively" being a key word. Even tropical storms can be massive systems with great destructive potential) With that in mind the National Hurricane Center has developed the Sea, Lake, and Overland Surge from Hurricanes, or SLOSH model.
While the acronym seems almost whimsical, there's nothing amusing about the information the model generated for the Tampa Bay region. As pointed out in a blog entry by Weather Underground founder Dr. Jeff Masters, the implications of a strike by a category 4 hurricane at high tide are grim. "The storm tide--the combination of the storm surge plus the 1 foot high tide--reaches as much as 27 feet above mean sea level (pink colors) near downtown Tampa (right-hand "maximum storm tide" image). The amount of inundation inland is controlled by the elevation of the land. Some of the inland regions near downtown Tampa being inundated by the 27-foot storm tide are at an elevation of 19 feet, so as much as 8 feet of inundation will occur at those locations (dark blue colors in the left-hand "maximum water depth" image)."
The Weather Underground website devotes many pages to detailed information about the realities and misconceptions that surround storm surge. It makes for disturbing reading, but it's information that could make the difference between making a good decision and life-threatening mistake.