Storm surge proxies in a data-poor landscape: a practical monitoring method for under-surveyed and -studied communities vulnerable to climate change

Abstract

The central problem we investigate is how coastal communities in the Arctic can plan for future storms in the absence of continuous, long-term data and/or instrumentation to monitor climatic events. The native village of Shaktoolik, Alaska recognizes these limitations and seeks increased monitoring of life-threatening storms affecting their village in their adaptation planning documents. To address this situation, and with the consent of the Tribal Council, we establish a baseline to monitor storm intensity in this data-poor region by dating and mapping storm surges in the Shaktoolik area. A storm surge is a proxy of storm intensity. We use driftwood in two ways to reconstruct past storm surges. First, we plot GPS points of driftwood lines on remote sensing imagery and digital elevation model data to map the maximum extent of storm surge for the November 2011 and 2013, and August 2019 storms. Second, in order to demonstrate that a particular log could have been deposited by those storms, dendrochronological analysis of individual logs within those deposits provides an estimate of when those trees died and could have entered the water as driftwood. These techniques, however, cannot determine the date of when those logs were deposited on a given beach. To narrow the date of the driftwood deposits from past storms, that is, to determine when the driftwood landed on the beach, local knowledge and observations are coupled with newspaper accounts. From these three lines of evidence, we show that the maximum storm surge the village can withstand without inundation is equivalent to the 2011 and 2019 storms. Those storms can be used as baseline indicators for future storms. This method of monitoring storm surges can be scaled up to other locations that also have minimal storm monitoring infrastructure.