As Hurricane Dorian approaches Florida, U.S. Geological Survey field crews are working along a 280-mile stretch of the state’s Atlantic coastline, installing instruments that will track the hurricane’s effects as it comes ashore. USGS scientists are also installing the instruments, which gather precise storm tide information, along the Georgia coast, and preparing for installations on Florida’s Gulf coast if the storm’s path warrants it.

On Thursday and Friday, Aug. 29 and 30, the USGS is deploying 18 field scientists to install scientific instruments at more than 60 locations along the Florida coast between Jacksonville and West Palm Beach. Some instruments are designed to measure the height and intensity of the storm surge if Dorian affects Florida’s Atlantic coast, as the National Hurricane Center forecasts it will. Others will monitor water levels on inland water bodies; the field crews will gather data from them immediately after the storm has passed.

In Georgia, field scientists will install 62 measuring devices the length of the state’s low-lying coastline, because slow-moving Hurricane Dorian may cause higher-than-normal ocean waves well to the north of the storm. Forecasters do not expect the hurricane to make landfall in Georgia.

Storm surge, coastal erosion and inland flooding are among the most dangerous natural hazards unleashed by hurricanes, with the capacity to destroy homes and businesses, wipe out roads, bridges, water and sewer systems, and profoundly alter landscapes. The USGS has storm surge experts, as well as sophisticated equipment for predicting and monitoring flood and tide conditions, and has been consulting with the National Hurricane Center and other agencies to prepare for Hurricane Dorian.

Prepared to Capture Coastal Storm Surges

Storm surges are increases in ocean water levels caused by extreme storms. Scientists want to better understand storm surges so forecasters can more accurately model and predict surge-related flooding, engineers can design better storm-resistant structures, and emergency responders can work more safely and effectively.

The USGS’ network of storm tide sensors along portions of the U.S. Atlantic and Gulf coastscan record water level and barometric pressure every 30 seconds to document storm surge crests, or waves of water, as they make landfall. Anticipating a storm’s path and intensity, USGS scientists often deploy storm tide sensors at other places along the coast just hours or days before a hurricane’s expected landfall. The sensors are housed in steel pipes a few inches wide and about a foot long. Working quickly, and often in severe weather, field crews install them on bridges, piers and other structures that have a good chance of surviving a hurricane’s storm surge. 

The USGS is installing storm tide sensors at 57 locations along Florida’s Atlantic coast. The teams are also deploying barometric pressure sensors, one within ten miles of every storm tide sensor; the two devices work together to correlate the storm’s intensity with wave heights. The crews also plan to deploy five clusters of wave height sensors on boardwalks in Flagler, Volusia, Brevard, St. Lucie and Palm Beach counties. By recording wave heights along a line running from the beach to the dune peak and behind the dune, these transects help create a detailed picture of wave action.

In Georgia, crews will install 50 storm tide sensors along the coast.

Adding Extra Streamgages to Track Dorian

The USGS Streamgaging Network operates scientific instruments that record water levels and other key pieces of information on rivers and streams throughout the nation, with the support of local, state, and federal agencies. During storms and floods the USGS uses this nationwide network to provide near-real-time data about water levels to the National Weather Service, Federal Emergency Management Agency, the U.S. Army Corps of Engineers, and others. 

When a major hurricane is expected to make a U.S. landfall, the USGS augments the network by installing special streamgages called rapid deployment gages, or RDGs, in areas where flooding is likely, but no permanent streamgage exists. RDGs measure water levels and local weather data in areas susceptible to storm-tide flooding and transmit that information by satellite in near-real time for flood forecasting and emergency response. 

Field crews expect to install threeRDGs along the Florida Atlantic coast and 12 in Georgia, completing the work in advance of Hurricane Dorian’s winds, rain and storm waves. If flooding does occur, USGS field crews will make real-time streamflow measurements to verify the streamgages’ readings. After the storm passes, the crews will quickly replace any storm-damaged or lost gauges. During and right after hurricane flooding, these records help FEMA target emergency relief to the hardest-hit areas.

Resources to Help Everyone Prepare

As USGS takes action to prepare for Hurricane Dorian, people in the path of the storm can get tips on creating emergency plans and putting together an emergency supply kit at www.ready.gov or www.listo.gov.

Photo: USGS hydrologist Patrick Ryan installed a storm-tide sensor at St. Augustine, Florida as Hurricane Matthew approached in 2016. Credit: USGS, public domain.