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Rapid Response To The Howard A. Hanson Dam Flood Risk Management Crisis

Abstract

The Howard A. Hanson Dam (HDD) has brought flood protection to Washington's Green River Valley for more than 40 years and opened the way for increased valley development near Seattle. However, following a record high level of water behind the dam in January 2009 and the discovery of elevated seepage through the dam's abutment, the U.S. Army Corps of 40   Engineers declared the dam unsafe. NOAA's Office of Oceanic and Atmospheric Research (OAR) and National Weather Service (NWS) worked together to respond rapidly to this crisis for the 2009/10 winter season, drawing from innovations developed in NWS offices and in NOAA's Hydrometeorology Testbed (HMT).   New data telemetry was added to 14 existing surface raingages allowing the gauge data to  be ingested into the NWS rainfall database. The NWS Seattle Weather Forecast Office produced   customized daily forecasts, including longer lead-time hydrologic outlooks and new decision support services tailored for emergency managers and the public - new capabilities enabled by specialized products from NOAA's National Centers for Environmental Prediction (NCEP) and from HMT. The NOAA Physical Sciences Division (PSD) deployed a group of specialized   instruments on the Washington Coast and near the HHD that constituted two atmospheric river 51   observatories (AROs) and conducted special HMT numerical model forecast runs. Atmospheric rivers (ARs) are narrow corridors of enhanced water vapor transport in extratropical oceanic storms that can produce heavy orographic precipitation and anomalously high snow levels, and thus can trigger flooding. The AROs gave forecasters detailed vertical profile observations of AR conditions aloft, including monitoring of real-time water vapor transport and comparison with model runs.

Article / Publication Data
Active/Online
YES
ISSN
Print 0003-0007/Online 1520-0477
Volume
93
Available Metadata
Accepted On
July 05, 2011
DOI ↗
Fiscal Year
Publication Name
Bulletin of The American Meteorological Society
Published On
January 01, 2011
Publisher Name
Amer Meteorological Soc
Print Volume
93
Print Number
2
Page Range
189–207
Submitted On
December 03, 2010
URL ↗

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