Revising evidence of hurricane strikes on Abaco Island (The Bahamas) over the last 700 years

Abstract

The northern Bahamas have experienced more frequent intense-hurricane impacts than almost anywhere else in the Atlantic since 1850 CE. In 2019, category 5 (Saffir-Simpson scale) Hurricane Dorian demonstrated the destructive potential of these natural hazards. Problematically, determining whether high hurricane activity levels remained constant through time is difficult given the short observational record (< 170 years). We present a 700-year long, near-annually resolved stratigraphic record of hurricane passage near Thatchpoint Blue Hole (TPBH) on Abaco Island, The Bahamas. Using longer sediment cores (888 cm) and more reliable age-control, this study revises and temporally expands a previous study from TPBH that underestimated the sedimentation rate. TPBH records at least 13 ≥ category 2 hurricanes per century between 1500 to 1670 CE, which exceeds the 9 ≥ category 2 hurricanes per century within 50 km of TPBH since 1850 CE. The eastern United States also experienced frequent hurricanes from 1500 to 1670 CE, but frequency was depressed elsewhere in the Atlantic Ocean. This suggests that spatial heterogeneity in Atlantic hurricane activity since 1850 CE could have persisted throughout the last millennium. This heterogeneity is impacted by climatic and stochastic forcing, but additional high-resolution paleo-hurricane reconstructions are required to assess the mechanisms that impact regional variability.

Centennial‐Scale Shifts in Storm Frequency Captured in Paleohurricane Records From The Bahamas Arise Predominantly From Random Variability

“…We determine active and quiet intervals in our pseudo sediment records using established methods (Donnelly et al., 2015; Lane et al., 2011; E. J. Wallace et al., 2019; Winkler et al., 2020) for comparison with the number observed in the South Andros sediment record (Figure ). Active intervals are defined as consecutive years when the 100‐year window event frequency is above an upper confidence limit encompassing the expected random variability of hurricane strikes at a site.…”

“…Documenting and dating event beds in sediment cores provides high resolution archives of TC activity at a location over thousands of years. In particular, collecting cores from blue holes in the Caribbean Sea have allowed for near‐annual resolution records extending back over a thousand years (Schmitt et al., 2020; van Hengstum et al., 2014; E. J. Wallace et al., 2019; Winkler et al., 2020). While there is a myriad of different storm properties (e.g., intensity, track, and size) that could influence storm surge at a site, both modern event attribution in these sediment cores (Lane et al., 2011; E. J. Wallace et al., 2019; Winkler et al., 2020) and hydrodynamic modeling of large suites of synthetic TCs passing the sites (Lin et al., 2014) indicate that the vast majority of storms that leave deposits are above some intensity threshold (>Category 2 or 3) and passing proximal (within <100 km) to the site.…”

“…These event‐based paleohurricane reconstructions indicate that there have been dramatic changes in recorded hurricane activity over the past two millennia (e.g., Brandon et al., 2013; Bregy et al., 2018; Donnelly et al., 2015; Lane et al., 2011; E. J. Wallace et al., 2019; Winkler et al., 2020). In particular, these records capture multidecadal to centennial‐scale periods with elevated frequency of hurricane strikes, “active intervals,” followed by extended time periods of relative quiescence, “quiet intervals.” Many studies have attributed these active and quiet intervals to changes in the large‐scale climatic boundary conditions (e.g., the Intertropical Convergence Zone [Donnelly et al., 2015; van Hengstum et al., 2016], North Atlantic Subtropical High [Baldini et al., 2016; E. J. Wallace et al., 2019], El Nino Southern Oscillation [Donnelly & Woodruff, 2007]).…”

“…These event-based paleohurricane reconstructions indicate that there have been dramatic changes in recorded hurricane activity over the past two millennia (e.g., Brandon et al, 2013;Bregy et al, 2018;Donnelly et al, 2015;Lane et al, 2011;E. J. Wallace et al, 2019;Winkler et al, 2020). In particular, these records capture multidecadal to centennial-scale periods with elevated frequency of hurricane strikes, "active intervals," followed by extended time periods of relative quiescence, "quiet intervals."…”

“…In particular, collecting cores from blue holes in the Caribbean Sea have allowed for near-annual resolution records extending back over a thousand years (Schmitt et al, 2020;van Hengstum et al, 2014; E. J. Wallace et al, 2019;Winkler et al, 2020). While there is a myriad of different storm properties (e.g., intensity, track, and size) that could influence storm surge at a site, both modern event attribution in these sediment cores (Lane et al, 2011; E. J.…”