Reconstruction of Prehistoric Landfall Frequencies of Catastrophic Hurricanes in Northwestern Florida from Lake Sediment Records

Abstract

Sediment cores from Western Lake provide a 7000-yr record of coastal environmental changes and catastrophic hurricane landfalls along the Gulf Coast of the Florida Panhandle. Using Hurricane Opal as a modern analog, we infer that overwash sand layers occurring near the center of the lake were caused by catastrophic hurricanes of category 4 or 5 intensity. Few catastrophic hurricanes struck the Western Lake area during two quiescent periods 3400–5000 and 0–1000 14C yr B.P. The landfall probabilities increased dramatically to ca. 0.5% per yr during an “hyperactive” period from 1000–3400 14C yr B.P., especially in the first millennium A.D. The millennial-scale variability in catastrophic hurricane landfalls along the Gulf Coast is probably controlled by shifts in the position of the jet stream and the Bermuda High.

A decadally-resolved paleohurricane record archived in the late Holocene sediments of a Florida sinkhole

“…One-sigma (black) and two-sigma (gray) age ranges are shown for each date, and a linear fit (black line) to the median of the highest probability one-sigma age ranges reveals a roughly constant sedimentation rate of 1.35 mm yr-1 throughout the 601 cm (or ~ 4450-year) record. One-sigma and two-sigma age ranges for the anomalous date at 268-269 cm, which was not included in the (Scileppi and Donnelly 2007), Western Lake in Florida (�) (Liu and Fearn 2000), and Mattapoisett Marsh in Massachusetts (�) (Boldt et al 2010) are shown alongside the LT (�) and HT (+) versions of the MLT1 record. MLT 1 Figure 1 -MLT1 and MLT2 radiocarbon-based age models.…”

“…When longer time periods are considered, changes in local hurricane frequency are more likely to reflect larger-scale changes in storm climate (Woodruff et al 2008a). Other sediment-based paleohurricane records from the Caribbean, Northeastern U.S., and the northern Gulf of Mexico have documented significant multi-centennial to millennialscale variability in hurricane frequency similar to the centennial to multi-centennial variability identified in the Mullet Pond reconstruction, though the timing and extent of the variability differs somewhat among the records (Liu and Fearn 1993, Liu and Fearn 2000, Scileppi and Donnelly 2007, Donnelly and Woodruff 2007. Fearn (1993, 2000) identified low-frequency variability in the number of visible sand layers deposited by hurricanes impacting Western Lake, Florida.…”

“…These proxies can be categorized into two main types: isotope-based proxies that rely on the detection of tropical cyclone rainfall signatures preserved in corals (Cohen 2001, Hetzinger et al 2008, tree rings (Miller et al 2006), and speleothems (Frappier et al 2007, Nott et al 2007, and sediment-based proxies such as cyclone surge-constructed beach ridges Hayne 2001, Nott et al 2009) and overwash deposits preserved in back barrier lagoons (Donnelly 2005, Donnelly and Woodruff 2007, Woodruff et al 2008a, Woodruff et al 2008b, Wallace and Anderson 2010, coastal lakes (Liu and Fearn 1993, Liu and Fearn 2000, Liu and Fearn 2002, Lambert et al 2003, Lambert et al 2008, and marshes (Donnelly et al 2001a, Donnelly et al 2001b, Donnelly et al 2004, Scileppi and Donnelly 2007, Boldt et al 2010. Isotope-based proxies have in some cases provided exceptional, sub-annual resolution; however, such records often span only a relatively short interval of time.…”

“…The Western Lake, Vieques and Alder Island records were developed from sites that are relatively difficult to inundate; therefore, these records likely documented only the largest hurricane-induced surges (Liu and Fearn 2000, Scileppi and Donnelly 2007, Woodruff et al 2008a, Woodruff et al 2008b. As suggested by their much higher paleohurricane frequencies, Mullet Pond and Mattapoisett Marsh are more susceptible to smaller storm surges and can be inundated by a broader range of surge events.…”

The origin of centennial- to millennial-scale chronological gaps in storm emplaced beach ridge plains

“…In the case of hurricane overwash deposits (Liu and Fearn, 2000;Donnelly and Woodruff, 2007;Woodruff et al, 2009) it is difficult to ascribe erosional processes to the gaps for the records are composed of sand layers sandwiched within fine-grained sedimentary units in back barrier lagoons. Chronological gaps within beach ridge plains that record long-term TC histories (Nott, 2003;Nott et al, 2009;Forsyth et al, 2010) are possible via two causes; erosion and removal of ridges or periods of slower or no ridge building possibly associated with a quiescence in intense TC activity.…”