North Pacific Extreme Storms Reconstructed With a Novel Approach to Estimating Storm Frequency and Uncertainty

Sedimentary archives of tropical cyclones have been primarily developed in back barrier settings and karst basins at low to mid‐latitude sites in the Atlantic. Here, a unique record of high‐latitude storms is presented from Skan Bay, Unalaska in the Eastern Aleutian Islands. Storm‐induced coarse deposits in a 20.5 m composite sediment core are identified and distinguished from deposits with other depositional sources using a combination of particle‐size analysis, CT‐scanning, and lithostratigraphy. Gaussian kernel density estimation is used to produce a continuous 3,000‐year record of centennial storm frequency. Bootstrapping is applied to estimate uncertainties on the inferred storm frequencies related to the limited sample size of a single sediment core and age‐control errors. Uncertainty estimates on the phasing of active and inactive storm‐frequency intervals are increased when all age‐depth scenarios are propagated into the error analysis compared to when only sampling uncertainty is considered. This work highlights the importance of accounting for chronological uncertainty in storm reconstructions, which is often overlooked and may affect climate interpretations. Results show that the timing of a storm frequency peak in Skan Bay during the Medieval Climate Anomaly (950–1250 CE) has a 90% confidence interval spanning the entire last millennium. This study demonstrates the viability of high‐latitude fjords as paleostorm recorders, fills an important spatial gap in the global paleotempestological record, and presents a methodological framework for performing more comprehensive uncertainty estimation on individual paleostorm records than in past studies.