North Atlantic Storm Activity During the Younger Dryas

Abstract:

The risks posed to cities along the Eastern Seaboard by a potential intensification of tropical cyclone activity over the coming decades remain poorly constrained, in part, due to a lack of available storm proxy records that extend beyond the relatively stable climates of the late Holocene. Previous work in the Bahamas shows that coarse-grained, high-energy event layers in carbonate bank margin sediments: (1) closely track recent historic hurricane events and (2) that the sensitivity of this proxy may be less affected by the deglacial changes in sea level that have limited our ability to reconstruct past hurricane activity using overwash records from back-barrier beach settings. Here we present a record of storm triggered turbidite deposition from a suite of well dated (e.g. Lynch-Stieglitz et al., 2011, Paleoceanography) jumbo piston cores taken offbank (300-500 mbsl) the Dry Tortugas, Florida, that spans abrupt transitions in North Atlantic sea surface temperature and thermohaline circulation during the Younger Dryas (12.9 - 11.5 kyr BP). This record, along with General Circulation Model output (TraCE: NCAR-CGD), indicates strong hurricane activity may have occurred along Southeastern US coasts through this interval despite considerably colder North Atlantic SSTs.