Geomorphic changes measured on Dauphin Island, AL, during Hurricane Nate

Abstract

Storm surge and waves from Hurricane Nate in 2017 resulted in large overwash and inundation regions on Dauphin Island, Alabama. The overwash event consisted of the transport of water and sediment over the beach, dune, and barrier island system. Seven transects were established to measure pre- and post-storm survey profiles. Nine wave and water level sensors were deployed in an overwash region and captured the overwash conditions including time-varying water levels and waves. All transects experienced a net loss of sediment from the subaerial region surveyed and a range of inundation and sediment overwash. The results highlight the limits of empirical estimates for evaluating the exposure of backdune regions to overwash and inundation.

Labeling Poststorm Coastal Imagery for Machine Learning: Measurement of Interrater Agreement

“…One option is to try to fuse these images with other existing data sources to develop ground‐truth data sets. For example, linking images with colocated field observations (e.g., Anarde et al., 2020; Coogan et al., 2019; Reeves et al., 2021), numerical model experiments (e.g., Gharagozlou et al., 2020), poststorm damage surveys (e.g., Kennedy et al., 2020; Zhai & Peng, 2020), or social media messages (Mohanty et al., 2021). Ground‐truth data can be used to assess whether the human labels are able to identify past processes from images.…”

Modeling of Barrier Breaching During Hurricanes Sandy and Matthew

“…Barrier island breaching can occur from inundation from either the ocean toward the back‐barrier, or vice‐versa. Several recent studies have discussed the importance of the ocean‐back‐barrier water level gradient in modulating the direction of overwash, inundation, and inlet currents (Coogan et al., 2019; Engelstad et al., 2017; Harter & Figlus, 2017; Passeri et al., 2018; Safak et al., 2016; Sherwood et al., 2014; Smallegan & Irish, 2017). The hydrodynamic processes that drive elevated ocean water levels include tides, sea level pressure (SLP)‐driven inverse barometer effect, baroclinic effects (Pringle et al., 2019), wind‐driven storm surge and wave run‐up.…”

“…Efforts to observe nearshore hydrodynamics in situ are often limited to a single transect in the cross‐shore (Engelstad et al., 2017; Sherwood et al., 2014). Large‐scale deployments including multiple cross‐shore transects (e.g., Coogan et al., 2019) illustrate that substantial alongshore variability in nearshore hydro‐ and morphodynamics can occur over small spatial scales during extreme events. Observations of active sediment transport or time‐varying morphological changes are further limited.…”

Remote bed-level change and overwash observation with low-cost ultrasonic distance sensors

“…Holland et al (1991) computed celerity vectors of overwash bores by analyzing video using large-scale particle image velocimetry, and calculated overwash depths using a cross-shore array of capacitance-style wave staffs. More recently, arrays of pressure transducers (Baldock et al 2008;Hoekstra et al 2009;Matias et al 2010;Sherwood et al 2014;VanDusen et al 2016;Coogan et al 2019;Lashley et al 2019;Anarde et al 2020) and current meters or velocimeters (Englestad et al 2017;Matias et al 2017Matias et al , 2019 have been used to measure overwash depths and hydrodynamics. Matias et al (2010) also used fluorescent tracers to track sediment pathways and plugs of contrasting sand to calculate mixing depths.…”