Hurricane Michael in the Area of Mexico Beach, Florida

Abstract

Category 5 Hurricane Michael made landfall near Mexico Beach, Florida on October 9, 2018, with measured high water marks (HWMs) reaching 7.2 m NAVD88. The town itself received great damage, with many areas destroyed down to the foundations. In this study, we document the storm and its effects on the greater Mexico Beach area: hazard, structural damage, and their relationships. Wave and surge damage was nearly total for low-lying properties, but damage decreased greatly with increasing elevation. Major wave and surge damage was noted in Federal Emergency Management Agency (FEMA) X zones, which are out of the 100-year floodplain, and it is suggested that the 100-year storm is a deficient measure for categorizing flood risk.

Scour Development and Possible Effects of Momentary Liquefaction in Inundated Coastal Areas During Hurricane Michael

“…In situ measurements of water depths and wave heights were collected by a United States Geological Survey (USGS) wave gage (FLBAY03283) located on the pier in Mexico Beach, FL, during Hurricane Michael (Kennedy et al 2020). The point gage was located approximately 55 m inland from the normal shoreline and at an elevation of 2.12 m North American Vertical Datum of 1988 (NAVD88).…”

“…The resulting destruction to infrastructure resulted in $25 billion in damages (NOAA 2019). The piles supporting onshore structures were inundated and subjected to waves and currents driven by the storm for approximately 3 h (Kennedy et al 2020). As a result, scour holes were observed in areas that were normally not at risk of scour (onshore piles located approximately 100 m or more from the shoreline).…”

“…However, Borga et al (2017) stated that limited inundation time, poorly defined flow geometry, and variability in flow velocity may create significant differences between riverine and offshore scour processes compared with onshore inundation scour processes. Floating debris and rapid changes in water depth are other factors that may be unique to storm-based inundation events (Kennedy et al 2020;USGS 2020). Additionally, onshore soils (onshore being defined for this study as located between 100 and 350 m from the shoreline during nonstorm conditions) have not been exposed to energetic hydrodynamic conditions (i.e., may not have developed natural armoring) and may have increased gas content compared with riverine or offshore sediments, both of which may increase the risk of scour for these sediments (Mory et al 2007;Vanoni 2014).…”

StEER: A Community-Centered Approach to Assessing the Performance of the Built Environment after Natural Hazard Events

“…However, this field response strategy requires a reasonable estimate of the hazard gradient as well as access to inventory data to inform target selection (transects or building clusters). To date, StEER has employed Hazard Gradient Surveys in both tornadoes and hurricanes, including sampling the performance of coastal structures across significant storm surge hazard gradients in events such as Hurricane Michael ( 2018) (Kennedy et al, 2020).…”

Research Needs, Challenges, and Strategic Approaches for Natural Hazards and Disaster Reconnaissance

“…processes representing the inter-related, destructive forcing mechanisms of natural hazards (Kennedy et al, 2020b and references therein). Specifically, modern reconnaissance instrumentation can capture rare, but critical, perishable data during and following natural hazards, including the quantification of inundation extent, flow speeds, flow depth, wave conditions, wind speeds, soil properties, erosion and accretion, and inundation-related damage to civil infrastructure and the natural environment (Kennedy et al, 2020a). These data help improve understanding of, for example, (a) the interplay between the natural landscape (land cover, topographic features), the built environment (critical infrastructure, homes), and hydrodynamics and (b) how and when concurrent multi-hazard components (e.g., wind vs. surge) lead to the functional failure of critical infrastructure-ultimately leading to more resilient communities (e.g., Baradaranshoraka et al, 2017).…”