The 2018 hurricane season got an early start with sub-tropical storm Alberto forming on May 25.
Scientists in the USGS National Assessment of Coastal Change Hazards Project Ready for 2018 Hurricane Season
This article is part of the June 2018 issue of the Sound Waves newsletter.
The 2018 hurricane season got an early start this year with sub-tropical storm Alberto forming on May 25. Scientists with the USGS National Assessment of Coastal Change Hazards (NACCH) project were ready to provide data and tools to guide response and recovery efforts for Alberto.
Since 2011, NACCH project researchers have provided forecasts of coastal erosion based on lidar-derived beach morphology and modeled storm waves and water levels. Scenario-based forecasts are updated every year using simulated hurricane waves and surge and the most recent beach morphology from the USGS. These scenarios can be used to plan for potential future storm impacts.
During a landfalling storm, storm-specific probabilities of coastal change are made using real-time waves and surge forecasts from NOAA. Both scenario-based and real-time forecasts of coastal erosion are available in the Coastal Change Hazards Portal and are updated as conditions change. During the extremely active 2017 hurricane season, project scientists posted 25 separate forecasts identifying where beaches along the Atlantic and Gulf coasts were at risk of dune erosion, overwashing, or inundation.
In collaboration with the National Weather Service (NWS), the NACCH project has also developed an Operational Total Water Level and Coastal Change Forecast Viewer. This viewer is updated several times a day with real-time water levels from the NWS Nearshore Wave Prediction System and is currently available for over 3000 kilometers of the Gulf of Mexico and Atlantic coasts from Florida through Maine. The viewer includes predictions of the timing and magnitude of water levels at the shoreline and potential impacts to coastal dunes. Observations collected by USGS water-science offices during Hurricanes Irma and Nate are being used to validate the model.
The NACCH project is constantly working to improve forecasts of coastal change through observations and research. Video cameras at Madeira Beach and Sand Key, Florida, collect observations of the coast that can be used to monitor a range of processes, such as beach and dune erosion during extreme storm events. These observations are used to evaluate models for predicting water levels at the shoreline driven by surge and waves, and to help improve our understanding of coastal processes during storms when traditional surveys are too dangerous.
Unmanned aircraft systems (UAS), commonly referred to as drones, are another tool for NACCH project scientists to obtain rapid-response observations of the coast. Equipped with a small digital camera, a UAS can be deployed to collect aerial imagery before and after storm events. With a flight time of 10-15 minutes, the UAS can capture images from a stationary position to create standard image products for extracting water levels, shoreline position, and bathymetry. Additionally, the UAS can fly along the coast capturing multiple snapshot images, from which elevation data can be extracted using a new technique termed structure-from-motion (SfM). Preliminary SfM analysis from Madeira Beach has been used to measure the changes due to Irma and subsequent recovery.