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Ross Dam, WA
Ross Dam, WA, Credit: USACE
Related Figure:
Correlation between Q2 radar-estimated precipitation and IRFREQ, original CMORPH, and KF CMORPH, plotted as a function of local time.
Fig. 15 from the paper: Conceptual representation of key atmospheric conditions associated with the top-10 annual peak daily flows observed in four watersheds in western Washington.
Click image for more detail
Contact:  Paul Neiman
July 8, 2011

HMT Publication Notice:

A journal article titled Flooding in Western Washington: The Connection to Atmospheric Rivers by Paul J. Neiman, Lawrence J. Schick, F. Martin Ralph, Mimi Hughes, and Gary A. Wick recently appeared on June 1, 2011 as a Journal of Hydrometeorology early online release.

As part of an ongoing research effort associated with HMT activities focused in the Pacific Northwest, this paper utilizes multi-decadal streamflow observations from four large watersheds in western Washington in conjunction with polar-orbiting SSM/I satellite imagery and the 32-km resolution North American Regional Reanalysis (NARR) gridded dataset to determine the meteorological conditions most likely to produce the largest annual discharges in those watersheds. The results demonstrate that atmospheric rivers (ARs) are responsible for these large discharges, and that the orientation and low-level flow direction within these ARs dictate which watersheds are most likely to flood. This research was motivated by storm damage incurred at the Howard Hanson Dam, and, subsequently, the dam's reduced capacity to store flood waters, immediately upstream of a major commercial hub (with billion of dollars of infrastructure and commerce) on the south side of Seattle. This work is the product of close cooperation between teams from NOAA/PSD in Boulder, CO and the U.S. Army Corps of Engineers in Seattle, WA.

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