As Hurricane Irma looks to be hurdling straight for a direct hit on Southern Florida, meteorologists from Weather Underground are warning that the most devastating impacts of the storm could be felt much further north in towns along the coast of Georgia and South Carolina where the storm surge could be a catastrophic 20-28 feet high in certain areas. To put that in perspective, Hurricane Katrina in 2005 set a record for the largest storm surge ever recorded along the U.S. coast at 27.8 feet.
If Irma makes a trek up the East Coast from Miami to southern South Carolina as a Category 3 or 4 hurricane, as the models currently suggest, the portions of the coast that the eyewall touches will potentially see a massive and catastrophic storm surge, breaking all-time storm surge records and causing many billions of dollars in damage. Even areas up to a hundred miles to the north of where the center makes landfall could potentially see record storm surges. The area of most concern is the northern coast of Florida, the coast of Georgia, and the southern coast of South Carolina, due to the concave shape of the coast, which will act to funnel and concentrate the storm surge to ridiculous heights. If we look at wunderground’s storm surge maps for the U.S. East Coast, we see that in a worst-case Category 3 hurricane hitting at high tide, the storm tide (the combined effect of the storm surge and the tide) ranges from 17 – 20’ above ground along the northern coast of Florida, and 18 – 23 feet above ground along the Georgia coast. If Irma is a Cat 4, these numbers increase to 22 – 28 feet for the coast of Georgia. This is a Katrina-level storm surge, the kind that causes incredible destruction and mass casualties among those foolish enough to refuse to evacuate.
So, which coastal towns are most at risk? As Weather Underground notes, Savannah in Southern Georgia could see a surge of up to 23 feet if Irma strikes as a Category 3 storm. Obviously, the surge would be even larger if Irma manages to maintain Cat-4 winds.