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Initial Results and Future Applications of a CONUS-wide Flash Flood Prediction System. Zachary Flamig [email protected] University of Oklahoma/School of Meteorology NOAA/National Severe Storms Laboratory In collaboration with: - PowerPoint PPT Presentation
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Initial Results and Future Applications of a CONUS-wide Flash Flood Prediction System
Zachary Flamig [email protected] University of Oklahoma/School of Meteorology
NOAA/National Severe Storms Laboratory
In collaboration with:
JJ Gourley Suzanne Van Cooten Yang Hong Humberto Vergara NOAA/NSSL NOAA/NSSL OU/CEES OU/CEES
October 25th, 2010 National Flood Workshop, Houston, TX
Looking inland…
Flash Flood on June 10th
Albert Pike Campground, AR20 Fatalities
AP Photos
Floods & Flash Floods around May 1stNashville, TN>$1 Billion in damage
Flash Flood on June 14th
Oklahoma City, OK>$1 Million in damage
Flash Flood Prediction?
State of the Art: Gridded Flash Flood Guidance* Distributed hydrologic model for
soil moisture accounting Rainfall/runoff model for runoff
potential prediction Static model for critical runoff
threshold estimation
*Schmidt, J., A. J. Anderson, and J. H. Paul, 2007: Spatially-variable, physically-derived flash flood guidance. Preprints 21st Conference on Hydrology, San Antonio, Amer. Meteor. Soc., 6B.2.
Ultimately derives rainfall threshold which if exceeded means flash flooding is occurring or will occur!X
Flash Flood Prediction
Observed PrecipitationObserved Precipitation
Forecast PrecipitationForecast Precipitation
Distributed Hydrologic Models
Distributed Hydrologic Models
time
time
Flood Exposure
Model
Flood Exposure
Model
$0 >$1M Crop Damage
Pro
babi
lity
$0 >$5M Property Damage
Pro
babi
lity
0 1,000 People Affected
Pro
babi
lity
Requirements:Flash Flood Scale (1 km2, Sub-Hourly Time Scale)Probabilistic (Ensemble) Prediction
National Mosaic and Multi-Sensor QPE (NMQ-)Flooded Locations And Simulated Hydrographs (FLASH)
Getting Observed Precipitation
NMQ Q2, radar only product
0.01º x 0.01º (~1km x 1km)
2.5 minute update
Long term reanalysis (soon!)
Precipitation Forecasts
Cloud resolving NWP from 4km2 to 1km2
HRRR primary candidate because it assimilates NMQ 3D radar reflectivity field
Hydrologic Models
CREST HL-RDHM
Jointly developed by OU/NASA Runs operationally over globe
Developed by NWS Runs operationally at RFCs
Simulated Threshold Frequency
Requires a long archive of precipitation (10+ years) Run the model using the precipitation archive Compute Log Pearson-III flood frequencies for
each grid cell
Return Frequency
Full ArchiveUSGS Q
14 YearUSGS Q
14 Year Simulated Q
2 Years 555 cms 549 cms 655 cms
5 Years 1119 cms 925 cms 841 cms
10 Years 1594 cms 1215 cms 959 cms
25 Years 2297 cms 1625 cms 1103 cms
50 Years 2888 cms 1962 cms 1207 cms
100 Years 3540 cms 2322 cms 1309 cms
USGS 07196500 Illinois River near Tahlequah, OK
Flood Exposure Model
Risk = Hazard (dynamic) * Vulnerability (static) Property damage
from ABRFC area for flash floods
Utilizes StormDat polygon data from 2006-2010
Only hazard information used in shown figure
Event Type: FloodStart Time: 6/27/2008 11:30 A.M.Latitude: 38.013824Longitude: -96.715266County: ButlerState: KansasFlood Nature: Overflow road otherDepth: 0.3 mLateral Extent: 300 mComments: Horse corral on location was flooded. Creek flooded 1/4 mile west from location. Road closed at 150th and Highway 77.
Verification Methods
1. NWS flash flood reports (StormDat)+ Designed to encompass all events in
forecaster’s area of responsibility- Dependent upon NWS warning
process, population density
2. 15-minute streamflow data from USGS
+ Objective measurement of discharge
- Need flashy basins with basin area < 260 km2 (flash flood scale)
- Flash flood defined as 2-year return period
3. SHAVE flash flood reports+ High spatial and temporal
resolution+ Flood characteristics- Database is storm-targeted; does
not encompass all flash flood events- Dependent on population density
Event Type: Flash FloodWFO: OUNBegin Date: 3/20/2007Begin Time: 9:30 A.M. CSTCounty: KayState: OK
Severe Hazards Analysis and Verification Experiment (SHAVE)* SHAVE reports are more
dense than NWS reports (e.g., 50:1)
Unique data collected in SHAVE Reports of no flooding Specific impact Lateral extent/depth/motion of
water Respondent-estimated frequency
Lightning Creek flooding, OKC July 2010
*Ortega, K.E., T.M. Smith, K.L. Manross, A.G. Kolodziej, K.A. Scharfenberg, A. Witt, and J.J. Gourley, 2009: The severe hazards and verification experiment, Bull. Amer. Meteor. Soc., 90, 1519-1530.
Lets see it!
Back to the Coast!
Distributed hydrologic model (HL-RDHM) run for Tar & Neuse basins.
Green dots represent verification points
Red dots are hand-off points for hydrodynamic ocean model (ADCIRC)
NMQ-FLASH will allow for distributed hydrologic model results from anywhere in the CONUS including other coastal areas (Texas, South Carolina, etc)
Real-time Simulations
Non-optimized ensemble produces reasonable spread already at this early stage; optimized ensemble from NMQ-FLASH will produce a spread that completely envelopes the observed hydrograph.
National Mosaic and Multi-Sensor QPE (NMQ-) Flooded Locations And Simulated Hydrographs (FLASH)
- A CONUS-wide flash-flood forecasting demonstration system
NMQ/Q2 Rainfall Observations-1km2/2.5 min
Stormscale Rainfall Forecasts
Stormscale Distributed Hydrologic Models
Probabilistic Forecast Return Periods and Estimated Impacts
10-11 June 2010, Albert Pike Rec Area, Arkansas
10”
8”6”
Q2
Q5
5 hr
Hydrograph of Simulated and Observed Discharge
Simulated surface water flowSimulated surface water flow
20 fatalities20 fatalities
80%
60%40%
Probability of life-threatening flash flood
t=2300
t=0000
t=0100
