Physical processes and mitigation techniques during ice-jam floods on the Yukon River, Alaska and Lena River, Sakha Republic

Lead Author Nikita, Tananaev
Institution Contact P.I. Melnikov Permafrost Institute, SB RAS, Yakutsk, Russia (University of Toulouse, France; Ugra Research Institute of Information Technologies, Russia)
Co-Authors Edward Plumb, National Weather Service, USA Jessica Cherry, University of Alaska Fairbanks, USA Alexei Kostin, Diamond and Precious Metal Geology Institute, Russia
Theme Theme 1: Vulnerability of Arctic Environments
Session Name 1.4 Vulnerability of Arctic Communities to Natural Disasters
Datetime Wed, Sep 14, 2016 03:45 PM - 04:00 PM
Presentation Type Oral
Abstract text Ice jams during spring breakup in the Arctic illuminate the intersection of environmental and social systems that lead to natural disasters. We compared circumstances leading to and following flood disasters in the similar towns of Galena on the Yukon and Edeytsy on the Lena in May 2013.

Both jams formed where they had formed before, at an abrupt bend in the river. The ice packs that jammed were 'local' in origin, not from upstream reaches. Although the severity of the Yukon breakup was attributed to an unusually cold spring followed by sudden warming, weather and breakup time in the Lena basin were normal. At Edeytsy, the Lena rose constantly at 0.12-0.15 m/h during two days in May (14-16 May), remained high for 3 days (16-19 May), and then drained in one day to the safe levels. The Galena jam formed on 26 May and broke on 29 May, at which time the river was backed up more than 60 km. For both towns, inundation was as severe as ever recorded.

Ice conditions on the Yukon are monitored primarily by satellite and aircraft and by resident ground observers; on the Lena by ground observers and drones (UAS). In the Edeytsy region, a multi-government group meets regularly beginning well before breakup to review conditions. There does not seem to be this level of early coordination in Alaska. Also in the Edeytsy, evacuation drills are conducted and the ice cut and sanded above known jam points before breakup. Both towns are still in need of better levee protection, but both now have better ability to shelter in place and rely less on evacuation.

In both countries mitigation methodologies are experience-based, with Russia having much more experience. Neither country is doing much research to test the efficacy of such methods or discover better ones.
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