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Abstract Lakes set in arctic permafrost landscapes can be susceptible to rapid drainage and downstream flood generation. Of many thousands of lakes in northern Alaska, hundreds have been identified as having high drainage potential directly to river systems and 18 such drainage events have been documented since 1955. In 2018 we began monitoring a large lake with high drainage potential as part of a long‐term hydrological observation network designed to evaluate impacts of land use and climate change. In early June 2022, surface water was observed flowing over a 30‐m wide bluff, with active headward erosion of ice‐rich permafrost soils apparent by late June. This overflow point breached rapidly in early July, draining almost the entire lake within 12 h and generating a 191 m3/s flood to a downstream creek. Water level and turbidity sensors and time‐lapse cameras captured this rapid lake‐drainage event at high resolution. A wind‐driven surface seiche and warming waters following ice‐out helped trigger the initial thermomechanical breach. We estimate at least 600 MT of lake sediment was eroded, mobilized, and transported downstream. A flood wave peaking at 42 m3/s arrived 14 h after the initial breach at a river gauge 9‐km downstream. Comparing this event with three other quantified arctic lake‐drainage floods suggests that lake surface area coupled with drainage gradient height can predict outburst flood magnitude. Using this relationship we estimated future flood hazards from the 146 lakes in the Arctic Coastal Plain of northern Alaska (ACP) with high drainage potential, of which 20% are expected to generate outburst floods exceeding 100 m3/s to downstream rivers. This fortunate and detailed drainage‐event observation adds to a growing body of research on the impact of lakes on arctic hydrology, hazard forecasting in a region with an increasing human footprint, and broader processes of landscape evolution in arctic lowlands.
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Research on the societal costs of disaster-related US school closures has focused, and due to COVID-19 will likely continue to focus, on pandemics, with very limited research on closures from natural hazards. This is surprising given that school closures occur frequently to protect children, teachers, and staff pre-event as well as post-disaster to convert facilities into emergency shelters, etc. This study investigates the secondary effects from post-flooding, temporary school closures after the catastrophic 2015 flash flood in Richland County, South Carolina. Lost productivity from school closures was quantified using the Human Capital Method. Out of the 208 completed surveys, 75% of households had children that missed school. Post-stratifying survey results on race produced an average of $437 in lost productivity due to school closures and an overall $2175 in lost productivity due to flood-related impacts in general. Expressed in FEMA benefit-cost analysis terms, our study shows that schools have a standard value of $215 per household and per day for the unweighted sample ($180 for the race-weighted sample). Furthermore, households' disutility for a late start is almost as great as their disutility for a school closure. These exploratory findings suggest that unplanned school closures should be minimized, and community characteristics carefully considered to avoid unintended socioeconomic consequences.more » « less
