JACKSONVILLE, Fla. – As we look back at Matthew, storm surge was moderate, running about 5-7 above normal, additionally, Matthew pushed past Jacksonville in between tides. Downtown saw about a 2 foot surge of water.
As Irma get closer and closer, different forecast models become more available to predict various severe weather impacts, including storm surge. On Thursday afternoon, the National Weather Service Office in Jacksonville released their initial forecast for storm surge flooding based on the available forecast track for Hurricane Irma.
The results were not encouraging. Oceanfront in Northeastern Florida may see 6 to 8 feet of above ground level storm surge flooding, especially in areas that were weakened structurally by Matthew. The St Johns River is expected to see 4 to 5 feet of above ground level storm surge water.
The initial storm surge forecast much higher for Southeastern Georgia- several factors contribute to this including the shape of the coastline, the angle that the storm will approach that coastline, and the elevation of the coastline. Hurricane Irma is expected to bring 10 to 13 feet of above ground level storm surge to Coastal Georgia. The rivers of coastal Georgia, like the Altamaha will see 10 to 14 feet of above ground level storm surge flooding.
Another aspect that will greatly impact the level of storm surge flooding damage is the level of tide during the height of the storm surge. Because of the roughly 48 hours of Northeasterly winds ahead of Irma, the tides are expected to already be running half a foot, to an entire foot below minor flood levels without any rise in levels from Irma.
Shifts in the track could greatly change the expected storm surge for each area. Regardless of the ultimate track of Hurricane Irma, because of the above normal tide levels and expected large waves and storm surge, the damage to the beaches and along the immediate coastline is likely to be significant, especially to those areas damaged by Matthew last year.
Our infastructure was damaged and remains weakened because of Hurricane Matthew last year, especially along the beaches. It will not require a direct hit to significantly damage A1A in Flagler and St Johns counties as well as the vulnerable beachfront homes.