1 AMBER Areal Mean Basin Estimated Rainfall COMET Faculty Course Robert S. Davis, Pittsburgh WFO

2 AMBER Overview AMBER Overview All watersheds in county warning area are defined to a Minimum Basin Area (MBA) of 2 mi 2 to show spatial rainfall distribution.All watersheds in county warning area are defined to a Minimum Basin Area (MBA) of 2 mi 2 to show spatial rainfall distribution. The WSR-88D polar grid (1 o by 1km) is mapped to the defined watersheds.The WSR-88D polar grid (1 o by 1km) is mapped to the defined watersheds. Average Basin Rainfall (ABR) is computed for each watershed every volume scan.Average Basin Rainfall (ABR) is computed for each watershed every volume scan. An hourly ABR rate is determined from the single volume scan (5-6 min.) of ABR.An hourly ABR rate is determined from the single volume scan (5-6 min.) of ABR.

3 National Basin Delineation 30Sep1999 – NWS agrees to fund the AMBER National Basin Delineation project by NSSL for all of the United States.30Sep1999 – NWS agrees to fund the AMBER National Basin Delineation project by NSSL for all of the United States. ArcInfo used to define the watershed boundaries.ArcInfo used to define the watershed boundaries. USGS 1 arc second (30 m) DEM data supplied by EROS Data Center.USGS 1 arc second (30 m) DEM data supplied by EROS Data Center.

4

5

6

7

8

9 Proposed and Applied on a Global Basis (GTOPO30) Kristine and John Verdin Senior Scientists EROS Data Center Journal of Hydrology 218 (1999) 1-12 Pfastatter System

10 Coding - Basins First requires identification of the four largest tributaries, according to the criterion of area drained.First requires identification of the four largest tributaries, according to the criterion of area drained. These are assigned the numbers 2, 4, 6, and 8, in the order in which they are encountered as one goes upstream along the main stem.These are assigned the numbers 2, 4, 6, and 8, in the order in which they are encountered as one goes upstream along the main stem.

11 Basin Boundary Streamline Basin Boundary Interbasin Boundary

12 The interbasins are numbered 1, 3, 5, 7, and 9, again working upstream from the mouth of the main stem.The interbasins are numbered 1, 3, 5, 7, and 9, again working upstream from the mouth of the main stem. Interbasin 1 is the area drained by the main stem between the mouth of basin 2 and the mouth of the main stem.Interbasin 1 is the area drained by the main stem between the mouth of basin 2 and the mouth of the main stem. Closed basin is assigned the number 0 (zero)Closed basin is assigned the number 0 (zero) Coding - Interbasins

13 Basin Boundary Streamline Basin Boundary Interbasin Boundary

14 Level 1 Pfafstetter subdivision of the North America

15

16 AMBER Watershed Division All watersheds in the county warning area are divided into hydrologic segments no larger than 10 mi 2.All watersheds in the county warning area are divided into hydrologic segments no larger than 10 mi 2. A Minimum Basin Area of 2 mi 2 is used in the initial NSSL stream creation procedure.A Minimum Basin Area of 2 mi 2 is used in the initial NSSL stream creation procedure. Each forecast office may modify the NSSL stream database (subdivide or aggregate).Each forecast office may modify the NSSL stream database (subdivide or aggregate).

17 AMBER 10 mi 2 Watersheds Operational 01May1985Operational 01May1985 Basins defined on “Fishing stream map of Pennsylvania.Basins defined on “Fishing stream map of Pennsylvania. Color Graphics display of WSR-57 rainfall estimates RADAP-II data (2 o x 1 nm grid)Color Graphics display of WSR-57 rainfall estimates RADAP-II data (2 o x 1 nm grid) 36 county map backgrounds with overlay of defined streams watersheds.36 county map backgrounds with overlay of defined streams watersheds. No ABR computation.No ABR computation.

18

19

20

21

22 Little Pine Creek Stage (ft) 30May1986 (UTC)

23

24

25

26 DHR WSR-88D Bin Assignment Polar grid 1 o by 1km DHR grid is mapped to all defined watershed segments. This allows ABR computation in 5-6 minute time steps.DHR grid is mapped to all defined watershed segments. This allows ABR computation in 5-6 minute time steps. DHR grid is mapped to all defined Urban Areas to compute ABR urban rainfall.DHR grid is mapped to all defined Urban Areas to compute ABR urban rainfall. Single 1km DHR bins are assigned to location of all rain gages, allowing gage comparison with radar estimated rainfall.Single 1km DHR bins are assigned to location of all rain gages, allowing gage comparison with radar estimated rainfall.

27

28

29 Pine Creek Aftermath RADAP-II provided excellent rainfall estimates for bucket survey gages and for ABR in watersheds down to 3mi 2.RADAP-II provided excellent rainfall estimates for bucket survey gages and for ABR in watersheds down to 3mi 2. Disaster survey team recommended that a 1-hour flash flood guidance (FFG) be initiated.Disaster survey team recommended that a 1-hour flash flood guidance (FFG) be initiated. Analysis of flash flood watersheds needed to be reduced from 10 mi 2 to at least 3mi 2.Analysis of flash flood watersheds needed to be reduced from 10 mi 2 to at least 3mi 2.

30 AMBER 3 mi 2 Watersheds Operational 01May1990 (RADAP-II data)Operational 01May1990 (RADAP-II data) MBR and ABR computations.MBR and ABR computations. 01June1993 WSR-88D Installed.01June1993 WSR-88D Installed. Operational 01May1996 (WSR-88D data)Operational 01May1996 (WSR-88D data) Watershed analysis accomplished on 7.5 minute topographic maps and MBA reduced to 3 mi 2.Watershed analysis accomplished on 7.5 minute topographic maps and MBA reduced to 3 mi 2. ABR computations only.ABR computations only.

31 Flash Flood Threat and ABR Severity of flash flooding is directly related to the observed ABR in a watershed.Severity of flash flooding is directly related to the observed ABR in a watershed. The time period of the ABR determines the ABR rate. The higher the ABR rate, the greater the risk of serious flash flooding.The time period of the ABR determines the ABR rate. The higher the ABR rate, the greater the risk of serious flash flooding. ABR varies as function of watershed area. As watershed area increases, ABR and ABR rate tend to decrease.ABR varies as function of watershed area. As watershed area increases, ABR and ABR rate tend to decrease.

32 FF Scale for Flash Flooding ABR in inches FF0 ABR = FFG to < FFG + 0.5FF0 ABR = FFG to < FFG FF1 ABR = FFG to < FFG + 1.5FF1 ABR = FFG to < FFG FF2 ABR = FFG to < FFG + 2.5FF2 ABR = FFG to < FFG FF3 ABR = FFG to < FFG + 3.5FF3 ABR = FFG to < FFG FF4 ABR = FFG to < FFG + 4.5FF4 ABR = FFG to < FFG FF5 ABR = FFG to < FFG + 5.5FF5 ABR = FFG to < FFG FF6 ABR = FFG or higher.FF6 ABR = FFG or higher.

33 ABR Rate Based on 5-6 minute observed ABR.Based on 5-6 minute observed ABR. Hourly ABR Rate = ABR x 3600/vsec, where vsec= the number of seconds in the volume scan.Hourly ABR Rate = ABR x 3600/vsec, where vsec= the number of seconds in the volume scan. ABR Rate is used to identify watersheds currently receiving the heaviest rainfall, before the flash flood producing accumulation occurs.ABR Rate is used to identify watersheds currently receiving the heaviest rainfall, before the flash flood producing accumulation occurs.

34 AMBER Z/R Gage Comparison The single 1km DHR bin that contains the rain gage is used to compute the radar rainfall estimate.The single 1km DHR bin that contains the rain gage is used to compute the radar rainfall estimate. Tropical vs. Standard Z/R usage can be estimated using 15 minute gage data.Tropical vs. Standard Z/R usage can be estimated using 15 minute gage data. Gage comparisons should be done to verify validity of the WSR-88D rainfall estimates.Gage comparisons should be done to verify validity of the WSR-88D rainfall estimates.

35 Pitcairn, PA Flash Flood 01-02July1997

36

37

38

39

40 Aber’s Creek # July mi 2

41 Thompson Run # July mi 2

42 Thompson Run Flooding Three feet of water was reported on Route 22 near the outflow of Thompson Run into Aber’s Creek at 2320UTC.Three feet of water was reported on Route 22 near the outflow of Thompson Run into Aber’s Creek at 2320UTC. Route 22 is the main parkway through the eastern suburbs of Pittsburgh.Route 22 is the main parkway through the eastern suburbs of Pittsburgh. The road was closed for almost an hour due to the high water.The road was closed for almost an hour due to the high water.

43

44 Dirty Camp Run # July mi 2

45 Dirty Camp Run(2) # July mi 2

46 Dirty Camp Run(1) # July mi 2

47 Dirty Camp Run(1-2) #6304/5 01July1997 ABR Rates

48

49

50

51

52

53

54 Pitcairn Flash Flooding About 10 million dollars of flood damage occurred in the city of Pitcairn.About 10 million dollars of flood damage occurred in the city of Pitcairn. Residents in Pitcairn reported that Dirty Camp Run was up near bankfull before the heavy rain began in town.Residents in Pitcairn reported that Dirty Camp Run was up near bankfull before the heavy rain began in town. The peak of the flooding in Pitcairn occurred from 01July/2330 UTC to 02July/0030 UTC.The peak of the flooding in Pitcairn occurred from 01July/2330 UTC to 02July/0030 UTC.

55 Tropical Z/R Cases Standard Z/R: Z = 300R 1.4Standard Z/R: Z = 300R 1.4 Tropical Z/R: Z = 250R 1.2Tropical Z/R: Z = 250R 1.2 Maximum Rate Cap 5.0 in/hr?Maximum Rate Cap 5.0 in/hr? Tropical Storm not required!!!Tropical Storm not required!!!

56 Standard and Tropical Z/R

57 AMBER Case Study Fort Collins, CO 28-29July1997

58

59

60

61 AMBER Case Study Dallas, Tx Flash Flood 05May1995

62

63 Dallas Mesonet Data 06May UTC

64 Dallas Mesonet Data 06May UTC

65 Dallas Mesonet Gage # May UTC

66 Kansas City, Mo Flash Flood 04-05October1998 The great Sunday night football flood

67 Kansas City, MO Flash Flood 04-05October1998 Severe flash flooding occurred on the Brush Creek and Turkey Creek watersheds.Severe flash flooding occurred on the Brush Creek and Turkey Creek watersheds. AMBER divides these two watersheds into 9 distinct hydrologic areas and computes Average Basin Rainfall (ABR) in each area.AMBER divides these two watersheds into 9 distinct hydrologic areas and computes Average Basin Rainfall (ABR) in each area. The next two slides depict the AMBER ABR using the standard and tropical Z/R rates.The next two slides depict the AMBER ABR using the standard and tropical Z/R rates.

68

69

70 Brush Creek (3) # October hour data

71 Brush Creek (3) # October min. data

72 AMBER Z/R Gage Comparison AMBER uses the single 1 o by 1km WSR- 88D range bin that contains the rain gage.AMBER uses the single 1 o by 1km WSR- 88D range bin that contains the rain gage. ABR is computed for this single bin and compared to the rain gage amount.ABR is computed for this single bin and compared to the rain gage amount. The Skywarn observer is located in the range bin centered on o at 46.5 km.The Skywarn observer is located in the range bin centered on o at 46.5 km. Area of the range bin at 46.5 km is 0.3 mi 2.Area of the range bin at 46.5 km is 0.3 mi 2.

73 NWS Skywarn # October min. data

74 Pittsburgh Urban Flash Flood July 28, 1999

75 Pleasant Hills IFLOWS 28July min. data

76 Castle Shannon IFLOWS 28July min. data

77 AMBER 1 mi 2 Watersheds Operational 01May1999Operational 01May1999 All streams in highly urbanized counties analyzed to a Minimum Basin Area (MBA) of 1 mi 2.All streams in highly urbanized counties analyzed to a Minimum Basin Area (MBA) of 1 mi 2. ABR computation for all streams, urban areas, and rain gages sites.ABR computation for all streams, urban areas, and rain gages sites.

78 Pittsburgh Urban Flash Flood May 18, 1999

79

80 AMBER Time Display Interval 5-minute ABR: Used to compute ABR Rate and to sum the ABR through a 2 hour time period.5-minute ABR: Used to compute ABR Rate and to sum the ABR through a 2 hour time period. 15-minute ABR: Used for comparison with IFLOWS rain gage data and to sum the ABR through a 6 hour time period.15-minute ABR: Used for comparison with IFLOWS rain gage data and to sum the ABR through a 6 hour time period. 1-hour ABR: Used for history of ABR in a watershed and to sum ABR through a 24 hour time period.1-hour ABR: Used for history of ABR in a watershed and to sum ABR through a 24 hour time period.

81 AMBER in AWIPS AMBER ABR computations, using the DHR 1 o x 1 km polar grid, should become available for Build 5.1 of AWIPS. (Late 2000 or early 2001)AMBER ABR computations, using the DHR 1 o x 1 km polar grid, should become available for Build 5.1 of AWIPS. (Late 2000 or early 2001) Build 5.0 of AWIPS will have no ABR computation, but will have a comparison of the HRAP 4 km grid FFG and WSR-88D HRAP 4km grid rainfall estimate (DPA product).Build 5.0 of AWIPS will have no ABR computation, but will have a comparison of the HRAP 4 km grid FFG and WSR-88D HRAP 4km grid rainfall estimate (DPA product).

82

83

84 24 Hour ABR-Rainfall History The history of ABR in a watershed for the past 24 hours can be compared with the MAP rainfall used to update FFG.The history of ABR in a watershed for the past 24 hours can be compared with the MAP rainfall used to update FFG. The AMBER 24 hour ABR product can be used to determine the rainfall distribution in any watershed for the previous hours.The AMBER 24 hour ABR product can be used to determine the rainfall distribution in any watershed for the previous hours. ABR is displayed in one hour increments with a running 24 hour total.ABR is displayed in one hour increments with a running 24 hour total.

85 Turtle Creek (1) ABR # May, hour data

86 Turtle Creek (1) ABR # May, minute data

87

88 Forest Hills Run ABR # May min. data

89 Forest Hills Run ABR # May min. data

90

91

92

93

94

95

96

97 Forest Hills EMA Reports 2215 UTC - First reports of water in basements.2215 UTC - First reports of water in basements UTC many cars stranded along Ardmore Boulevard UTC many cars stranded along Ardmore Boulevard UTC - 10/homes/20 people evacuated on Kenmore Avenue.0056 UTC - 10/homes/20 people evacuated on Kenmore Avenue.

98

99 Mon Valley Urban Areas Total population 86,565 Rankin/Braddock 8, mi 2Rankin/Braddock 8, mi 2 Clairton 12, mi 2Clairton 12, mi 2 McKeesport 31, mi 2McKeesport 31, mi 2 Glassport 6, mi 2Glassport 6, mi 2 Port Vue 5, mi 2Port Vue 5, mi 2 Wilson/Dravosburg 11, mi 2Wilson/Dravosburg 11, mi 2 Duquesne 10, mi 2Duquesne 10, mi 2 Liberty 3, mi 2Liberty 3, mi 2

100 Braddock Lock 2 ABR # May min. data

101 Braddock Lock 2 ABR # May min. data

102 Conclusions Small watersheds definition is the key to detection of flash flooding.Small watersheds definition is the key to detection of flash flooding. ABR Rate gives early warning for flash flood potential.ABR Rate gives early warning for flash flood potential. Time duration of rainfall display impacts forecaster perception of flash flood threat.Time duration of rainfall display impacts forecaster perception of flash flood threat. User selectable time window needed.User selectable time window needed.

103 AMBER Summary ABR provides basin specific rainfall to determine flash flood risk (ABR-FFG)ABR provides basin specific rainfall to determine flash flood risk (ABR-FFG) ABR rate focuses forecaster attention on critical streams before flooding occurs.ABR rate focuses forecaster attention on critical streams before flooding occurs. History of ABR helpful in adjusting FFG for multiple rainfall events.History of ABR helpful in adjusting FFG for multiple rainfall events. Basin specific ABR allows forecaster to mention “threat area” in warning text.Basin specific ABR allows forecaster to mention “threat area” in warning text.

104 AMBER Data Sources ArcView and the spatial analyst extension. and the spatial analyst extension. USGS Data (3 arc second DEM data) edcwww.cr.usgs.govUSGS Data (3 arc second DEM data) edcwww.cr.usgs.gov EPA Data (RF3 data files) Data (RF3 data files) Ami Arthur Arthur (SOO (SOO KHNL)

105 AMBER Case Studies ftp public buff.ppt 13Jul96buff.ppt 13Jul96 epgh99.ppt 18May99epgh99.ppt 18May99 pitcairn.ppt 01Jul97pitcairn.ppt 01Jul97 zion.ppt 27Jul98zion.ppt 27Jul98 ohio98.ppt 26Jun98ohio98.ppt 26Jun98 dallas95.ppt 05May95dallas95.ppt 05May95 ftc97.ppt 28Jul97ftc97.ppt 28Jul97 kc1998.ppt 04Oct98kc1998.ppt 04Oct98 Buffalo Creek, COBuffalo Creek, CO Pittsburgh, PAPittsburgh, PA Cedar City, UTCedar City, UT Eastern OhioEastern Ohio Dallas, TXDallas, TX Fort Collins, COFort Collins, CO Kansas City, MOKansas City, MO