Pittsburgh Urban Flash Flood May 18, 1999

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

Turtle Creek (1) ABR # May, hour data

Turtle Creek (1) ABR # May, minute data

Forest Hills Run ABR # May min. data

Forest Hills Run ABR # May min. data

Forest Hills Run in Park looking downstream.

Forest Hills Run exits the park under Route 30.

Forrest Hills Run underground. Notice new cement in storm drain. Kenmore Avenue Natural creek channel between Taco Bell and house.

Dumpster at Vincent’s Pizza washed 1 mile downstream along Electric Ave. Water and mud damage in building.

Electric Ave. Road is built on Forrest Hills Run creek bed, buried underground.

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.

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

Port Vue # mi May min. data

Port Vue # mi 2 18May min. data

Rankin/Braddock # mi May min. data

Rankin/Braddock # mi 2 18May min. data

Liberty # mi May min. data

Liberty # mi 2 18May min. data Liberty # mi 2 18May min. data

Duquesne # mi May min. data

Duquesne # mi 2 18May min. data

Clairton # mi May min. data

Clairton # mi 2 18May min. data Clairton # mi 2 18May min. data

AMBER’sSlidingTime Window AMBER’s Sliding Time Window AMBER gives the forecaster the option of examining rainfall in any time duration.AMBER gives the forecaster the option of examining rainfall in any time duration. The capability of examining rainfall in a moving time window is a very powerful feature for the flash flood forecaster.The capability of examining rainfall in a moving time window is a very powerful feature for the flash flood forecaster. One inch of rain falling in 15 minutes produces a much large stream response than one inch of rain distributed through 1 hour.One inch of rain falling in 15 minutes produces a much large stream response than one inch of rain distributed through 1 hour.

Clairton # mi 2 18May min. data

Clairton # mi 2 18May min. data Clairton # mi 2 18May min. data

24 Hour ABR-Rainfall History The history of previous rainfall in a watershed is invaluable in determing flash flood potential.The history of previous rainfall in a watershed is invaluable in determing flash flood potential. The AMBER 24 hour rainfall product can be used to quickly determine the rainfall distribution in any watershed for the past 24 hours.The AMBER 24 hour rainfall product can be used to quickly determine the rainfall distribution in any watershed for the past 24 hours. ABR is displayed in one hour increments.ABR is displayed in one hour increments.

Clairton # mi 2 18May hour data Clairton # mi 2 18May hour data

Glassport # mi May min. data

Glassport # mi 2 18May min. data

Thompson Run(1) # mi May min. data

Thompson Run(1) # mi 2 18May min. data

Thompson Run(2) # mi May min. data

Thompson Run(2) # mi 2 18May min. data

Braddock Lock 2 ABR # May min. data

Braddock Lock 2 ABR # May min. data

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.