Hurricane Ian made landfall in southwest Florida near Cayo Costa September 28, bringing with it extreme storm surge, category 4 winds, and a deluge of rain. The number of deaths associated with the storm will take time to determine, but the widespread damage to homes, businesses and infrastructure in Florida is immediately visible.

After preparing for Hurricane Ian’s first U.S. landfall by deploying scientific equipment to measure storm surge and coastal flooding, USGS scientists, technicians and staff in Florida took shelter and waited out the storm. Now, along with their families, friends, and neighbors, they are taking stock of Ian’s effects across Florida.

Meanwhile, for the past several days, USGS scientists and crews from neighboring states have been installing additional equipment along the Atlantic coasts for Ian’s second U.S. landfall, which happened this afternoon near Georgetown, South Carolina.

Repairing streamgages and measuring rivers and streams

In Florida, USGS crews are back out in the field repairing vital streamgages damaged by Ian and taking flood measurements. This ensures the National Weather Service and local communities have the best available water level and flow information, which is used by flood forecasters and emergency managers to make forecasts and decisions that protect lives and property.

Preliminary data indicates that at least 20 USGS streamgages in Florida have set new peaks of record, which indicates these gauges recorded water at the highest levels ever measured at their locations. The number of records is likely to change over the next week as streamgages are repaired and as floodwaters from the storm move downstream into receiving rivers.

Ian’s Second U.S. Landfall

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USGS field crews in Georgia, South Carolina, Virginia, Maryland and Delaware have been installing scientific equipment for days to measure and monitor the storm surge and coastal and inland flooding Ian is expected to bring with its second U.S. landfall in South Carolina. Preinstalled real-time water level sensors were also activated along North Carolina’s coasts to measure Ian’s impacts. In addition to installations, USGS water science centers across the southeast have been preparing crews and equipment to respond to and measure the flooding forecasters are predicting Ian will cause.

Earlier this week, USGS coastal change experts forecast Hurricane Ian would cause significant coastal impacts along the Gulf Coast of Florida and now they are forecasting coastal impacts in South Carolina and Georgia from Ian’s second U.S. landfall.

Recovering data to determine levels of coastal and inland flooding

Prior to Ian’s first and second U.S. landfalls, USGS crews deployed hundreds of storm tide sensors along the Gulf and Atlantic coasts. These instruments record the magnitude of the storm tide and waves that Ian caused.

Now that the storm is passed in Florida, USGS crews have begun collecting these sensors and processing their data. In the coming days after Ian passes, crews from Georgia to Delaware will return to the field to collect the sensors installed before the storm. These data serve not only to document the surge event from Ian, but also provides data to scientists and forecasters so they can improve storm surge and coastal change models. The information these models provide can be used to make communities more resilient to future storms. 

In parallel, USGS scientists will undertake a broad effort to find and survey high-water marks in coastal and inland flooded areas. These will help give scientists and communities a true understanding of the overall flooding caused by Hurricane Ian.

Since high-water marks are fragile and rarely last longer than a few days, it is important the work to find and survey them be completed as soon as possible. To aid in that effort, USGS crews from all over the Southeast have volunteered to deploy to the areas effected by Ian to assist local USGS offices with this important work.