Tropical Storm Allison

1
Tropical Storm Allison its impact on Harris
County

• Binbin Chen

2
Introduction

• Tropical Storm Allison formed 80 miles off the
  coast of Galveston, Texas on June 5, 2001
• Over the next 5 days, Allison produced
  record-setting rainfall, flooding and damage in
  Harris County and city of Houston
• Because of the magnitude of flooding, Harris
  County Flood Control District and FEMA specially
  performed a project Tropical Storm Allison
  Recovery Project (TSARP)

3
Flooding after Allison
22 fatalities
95,000 damaged automobiles
73,000 damaged residences
Over 5 billion in property damage
4
Project Purpose

• Perform an evaluation of the storm and its
  consequences in Harris County
• Storm Track
• Precipitation
• Stream discharge
• Flooding area
• Better understand water resource data and how to
  integrate different source data using ArcGIS

5
Data Sources

• National Hurricane Center provides historical
  tropical ecyclone track GIS data at
  http//maps.csc.noaa.gov/hurricanes/viewer.html
• National Climate Data Center provides NEXRAD
  Radar rainfall data at http//lwf.ncdc.noaa.gov/o
  a/radar/radarresources.html
• NHD (Unit 1204) NHDplus (Unit 12a) provide
  surface water data of Harris County
• USGS stream gages real time data
• Harris County Flood Control District Provides
  Harris County watersheds data and flooding area
  data
• City of Houston provides city land use data

6
Storm History Track
7
Storm Precipitation

• Rain gages
• -150 rain gages operated by Harris County Office
  of Emergency Management (HCOEM)
• -3 rain gages operated by National Weather
  Services (NWS)
• Radar data
• -NWS collected rainfall radar data at WSR-88D
  radar site covering the Houston area

8
Obtaining rainfall data
Visualize data in NEXRAD Viewer
Visualize data in NEXRAD Viewer
Downloaded raw radar data
Download raw radar data
Export radar data into ESRI raster data using
NEXRAD exporter
Export radar data into ESRI raster data using
NEXRAD exporter
9
Storm Total Rainfall
One Rain gage at Greens Bayou recorded the
highest rain as 38 inches.
10
Total Rainfallfrom June 5 to June 7
11
(No Transcript)
12
14-hour Rainfall
13
Source TSARP report
14
Stream discharge
15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
Source TSARP report
22
Flooding Area
23
(No Transcript)
24
Flooding land in Houston
25
Flooded Major Roads
26
Conclusion

• Tropical Storm Allison was the most damaging
  tropical storm in Harris County.
• Harris County received the heaviest rainfall from
  Tropical Storm Allison
• Streams in Harris County were greatly affected by
  Tropical Storm Allison, 17 out of 44 stations
  reached record peak flow on June 19,2001
• A large amount of lands roads in Harris County
  were flooded.
• ArcGIS has the powerful function to integrate
  different source data, visualize and analyze
  data, and depict a clear picture of the storm
  event, which helps people understand flooding and
  flood risk and better prepare for the next
  Allison.

27
Questions?