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Snowfall Observations and Products in the 21 st Century: Meeting the Needs of FEMA and the Climate Community. 2011 Snow Workshop Estes Park, Colorado. May 25, 2011. Jay H. Lawrimore NOAA’s National Climatic Data Center. Overview.
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Snowfall Observations and Products in the 21st Century:Meeting the Needs of FEMA and the Climate Community 2011 Snow Workshop Estes Park, Colorado May 25, 2011 Jay H. Lawrimore NOAA’s National Climatic Data Center
Overview • Since the 1990s FEMA has relied on a comparison of historical and current snowfall observations to determine if a county qualifies for snow disaster assistance • Historical observations provided by NCDC’s Snow Climatology dataset • Cooperative Observers Network (COOP) • Current observations from • Official NOAA observations (COOP, ASOS snow paid, Contract) • More recently other observations have been allowed (NWS Spotter, CoCoRaHS)
Snow Assessment Hurdles • The assessment process has not always been easy • Historical record that varies in length of record, spatial density, temporal completeness • 100-year record more likely to produce a greater snowfall extreme than a station with a 15-year • A county with 10 stations has a greater likelihood of having a higher extreme than a county with 2 stations (all other things being equal) • Current observations of the event in question are for some counties • Few and far between • Hard to obtain • Questionably measured
A Forecast Office Perspective • During the winter of 2009-2010, accurate snow measurements were a real laugh in the plains states. As a result some counties could not get $$$ from FEMA because the only source of measurement was a single coop observer in that county who probably under reported snowfall due to extremely high winds. Shelby county Iowa was denied $$$ while every surrounding county qualified. Those qualifying snow observations in surrounding counties were just as much a "best guess" as were the reports in Shelby county. • Seems to me FEMA should use more of a "mosaic" to determine snowfall in extreme cases like this one. If FEMA would have allowed road closure reports and photos of 20 to 30 foot drifts in cut outs where not even a large rotary blower could penetrate, then Shelby county would have qualified. In this case, if there had not been a coop site in Shelby county, FEMA would have used reports from the nearest stations and then Shelby county would have received the emergency aid.
Improving Quality of Observations • Objective: Develop recommendations for standardizing snowfall measurement practices across networks, with special focus on: • (1.1) Observing Procedures • (1.2) Training Tools and Methods • (1.3) NWS Spotter and other unofficial data sources
Improving Quantity (and Quality) • Objective: Identify ways to expand the network of high quality snowfall observations, with special focus on: • (2.1) Establishing methods for incorporating additional data sources (manual or automated) that meet established quality standards • (2.2) Refining the work plan for 2011-2012 NOAA/RCRN automated snow measurement study • (2.3) How FEMA and States can best fill gaps by using existing sources of data.
Improving the Historical Record • Objective: Identify methods for resolving inadequacies in existing snow climatologies and data accessibility within NOAA, with special focus on: • (3.1) Quality control of historical data • (3.2) Methods for resolving data density limitations • (3.3) Improved solutions to web-based delivery of snow data and products
Hail Reporting Practices • Objective: (4.1) Develop recommendations for changes to NWS Directives that will clarify and standardize hail reporting practices across COOP and ASOS networks to preserve the snow record.