USGS Scientists Tracking Hermine’s Effects on Florida, the Northeast

Release Date:

Working quickly, making decisions based on the National Hurricane Center’s latest forecasts, often working in storm winds and rain, USGS scientists use a variety of techniques to forecast and track coastal flooding caused by Hermine.

Ray Dupuis, U.S. Geological Survey hydrologic technician, begins to repair a USGS streamgage in Homosassa Springs State Park, Fl
Ray Dupuis, U.S. Geological Survey hydrologic technician, begins to repair a USGS streamgage in Homosassa Springs State Park, Florida, that was damaged by storm surges brought by Hurricane Hermine. Photo by Don Hampton, USGS. 

As the storm that struck Florida as Hurricane Hermine heads for a potential Labor Day weekend encounter with the Northeast coast, USGS scientists in eight states are gathering information that will help weather forecasters, coastal managers and residents prepare for this storm, and forecast future ones.

Working quickly and making decisions based on the National Hurricane Center’s latest forecasts of the storm’s track, USGS scientists in Florida, the Mid-Atlantic and New England use sophisticated water-level sensors especially designed for fast deployment to measure storm-tide and waves along sections of the coast where storm-surge and coastal flooding seem likeliest.

During a storm these sensors record the precise time a storm tide arrives, the depth of the storm tide throughout the event, the height and frequency of storm-driven waves, the change in inland and ocean water levels during the storm, and the time it takes for the water to recede. The information is useful to NOAA, local emergency managers and other agencies responding to storm surge and coastal flooding. It also helps scientists develop more accurate storm-tide models, leading to better predictions of flooding ahead of storms and better simulations of future flood patterns and trends. Ultimately, the information helps make it possible to build more resilient coastal communities. Information collected from these sensors is available to the public at https://water.usgs.gov/floods/FEV.

A few hours before Hermine struck Florida’s Big Bend around 1 a.m. Friday, Sept. 2, USGS scientists were out installing storm-tide sensors and barometric pressure monitoring devices from Apalachicola to Cedar Key. Working late into the evening on Sept. 1 as tropical storm force winds began reaching the coast, USGS teams installed the storm-tide sensors, which are housed in vented steel pipes a few inches wide and about a foot long, on bridges, piers, and other structures that have a good chance of surviving a hurricane’s storm-surge. The sensors’ information will help officials assess storm damage, distinguish between wind effects and flood damage, and improve computer models used to forecast future floods.

One preliminary reading from a permanent USGS streamgage at the mouth of the Aucilla River, near where Hermine made landfall at St. Marks, showed a storm surge of about 6 feet above normal high tide, said Richard Kane, associate director of the USGS’ Caribbean-Florida Water Science Center. The National Hurricane Center had predicted Hermine’s highest storm surge would occur in that area, and the actual reading approximately matched forecasters’ predictions, Kane said.

A similar intensive information-gathering effort was underway further up the Atlantic coast on Friday and Saturday, as USGS teams began deploying more than 65 storm-surge and barometric pressure sensors from Lewes, Delaware to Cape Cod, Massachusetts. The locations for these sensors were selected from among a network of 763 sites that have been prepared in advance to receive the rapid deployment devices. The network, set up in 2014, dramatically decreases the time it takes to provide FEMA, NOAA and other agencies information they need to help tailor their flood response and recovery efforts. It also includes a variety of coastal land types, from barrier islands and wetlands to urban areas, to help researchers develop a fuller picture of the storm-tide and wave effects.

A U.S. Geological Survey hydrologic technician, uses an Acoustic Doppler Velocimeter to measure stream flow on a Florida creek.
Neil Yobbi, U.S. Geological Survey hydrologic technician, uses an Acoustic Doppler Velocimeter to measure stream flow on Curlew Creek in Tampa, Florida, September 2. While Hurricane Hermine might have made landfall almost 200 miles away in St. Marks, Florida, a USGS rain gauge in Pinellas County, Florida, still measured more than 16 inches of total rain during the three-day storm event. Photo by Suzana Fuentes, USGS. Public domain. ​​​​​​​

Beach erosion is especially hard to track and predict, because the shifting sands tend to wash away the information-gathering devices that scientists need. The USGS is using two different strategies to monitor Hermine’s effect on beaches.

At Virginia’s Chincoteague Island, a popular tourism site and one prone to heavy beach loss from erosion, UGSS crews have designed an experimental system for housing storm-tide instrumentation inside steel pipes that can be driven into the sand deeply enough that they may outlast the storm. The scientists placed a row of the experimental devices on the island’s beach once it seemed likely Hermine might affect Virginia’s Eastern Shore.

A sophisticated coastal change forecast model, developed by scientists at the USGS’ St. Petersburg Coastal and Marine Science Center, is predicting that once Hermine returns to Atlantic Ocean waters, its waves will cause dune erosion along much of the Atlantic Coast from Virginia to New York, said research oceanographer Hilary Stockdon, who led the model’s development.

arge waves and surge associated with Hurricane Hermine cover Sunset Beach eating away at the sand dunes.
Large waves and surge associated with Tropical Storm Hermine cover Sunset Beach on Treasure Island, Florida, September 1, eating away at the sand dunes. The stakes seen in this photo are used to help measure how high the waves and surge reach. Photo by Jenna Brown, USGS.
​​​​​​​

The coastal change forecast model works with information from the National Hurricane Center’s storm surge predictions and NOAA wave forecast models, which describe storm waves’ heights and the timing between them. The USGS model adds information about the beach slope and predicts how far a storm’s large waves will push water up the beach. The forecast provides information for Gulf and Atlantic sandy beaches every kilometer (just under two-thirds of a mile). When a hurricane is expected to strike the U.S. coast, the model shows three types of likely impacts - beach erosion, dune overwash and coastal inundation – for the predicted area of landfall.

In the case of Hermine, dune erosion is likely along many beaches in Virginia and New Jersey, while dune overwash may occur in a few places, Stockdon said. The information is available to the public at the USGS’ Coastal Change Hazards Portal.

One area hard-hit by Hermine was Florida’s Tampa Bay region, where the storm’s rain bands lingered for three days, dumping a total of more than 16 inches of of rain that resulted in moderate to high flooding. USGS crews are out measuring flooding at existing gauges there. The data gathered from these devices will allow them to reconstruct every moment of flooding, visualizing how floodwaters interact with bays, estuaries and streams, and with local topography like beaches and dunes. The more knowledge they glean about these processes, the better equipped they will be to predict future storm surges and storm-related flooding.

At Treasure Island, near Tampa Bay, USGS researchers measured extensive dune erosion caused by Hermine, Stockdon said.

For more information, please visit the following websites: