Introduction

Storms and other severe weather events can cause both public health and economic problems for communities and municipalities. Many severe events can result in fatalities, injuries, and property damage, and preventing such outcomes to the extent possible is a key concern of this project.

Synopsis

This project involves exploring the U.S. National Oceanic and Atmospheric Administration’s (NOAA) storm database. This database tracks characteristics of major storms and weather events in the United States, including when and where they occur, as well as estimates of any fatalities, injuries, and property damage.

The analysis on the storm event database revealed that tornadoes are the most dangerous weather event to the populations health. The second most dangerous event type is excessive heat. The economic impact of weather events was also analyzed. Flash floods and thunderstorm winds caused billions of dollars in property damages between 1950 and 2011. The largest damage to crops were caused by droughts, followed by floods and hailing.

Data Preprocessing

suppressMessages(library(R.utils))
suppressMessages(library(dplyr))
suppressMessages(library(ggplot2))
if(!file.exists('storm_data.csv.bz2')){ ## if the source file not already downloaded
  download.file('https://d396qusza40orc.cloudfront.net/repdata%2Fdata%2FStormData.csv.bz2', 'storm_data.csv.bz2')
  
  ## if the zip file not extracted yet
  if(!file.exists('storm.csv')){
    bunzip2('storm_data.csv.bz2', 'storm.csv')
  }
}
storm <- read.csv('storm.csv', header = TRUE)
summary(storm)
##     STATE__                  BGN_DATE             BGN_TIME     
##  Min.   : 1.0   5/25/2011 0:00:00:  1202   12:00:00 AM: 10163  
##  1st Qu.:19.0   4/27/2011 0:00:00:  1193   06:00:00 PM:  7350  
##  Median :30.0   6/9/2011 0:00:00 :  1030   04:00:00 PM:  7261  
##  Mean   :31.2   5/30/2004 0:00:00:  1016   05:00:00 PM:  6891  
##  3rd Qu.:45.0   4/4/2011 0:00:00 :  1009   12:00:00 PM:  6703  
##  Max.   :95.0   4/2/2006 0:00:00 :   981   03:00:00 PM:  6700  
##                 (Other)          :895866   (Other)    :857229  
##    TIME_ZONE          COUNTY           COUNTYNAME         STATE       
##  CST    :547493   Min.   :  0.0   JEFFERSON :  7840   TX     : 83728  
##  EST    :245558   1st Qu.: 31.0   WASHINGTON:  7603   KS     : 53440  
##  MST    : 68390   Median : 75.0   JACKSON   :  6660   OK     : 46802  
##  PST    : 28302   Mean   :100.6   FRANKLIN  :  6256   MO     : 35648  
##  AST    :  6360   3rd Qu.:131.0   LINCOLN   :  5937   IA     : 31069  
##  HST    :  2563   Max.   :873.0   MADISON   :  5632   NE     : 30271  
##  (Other):  3631                   (Other)   :862369   (Other):621339  
##                EVTYPE         BGN_RANGE           BGN_AZI      
##  HAIL             :288661   Min.   :   0.000          :547332  
##  TSTM WIND        :219940   1st Qu.:   0.000   N      : 86752  
##  THUNDERSTORM WIND: 82563   Median :   0.000   W      : 38446  
##  TORNADO          : 60652   Mean   :   1.484   S      : 37558  
##  FLASH FLOOD      : 54277   3rd Qu.:   1.000   E      : 33178  
##  FLOOD            : 25326   Max.   :3749.000   NW     : 24041  
##  (Other)          :170878                      (Other):134990  
##          BGN_LOCATI                  END_DATE             END_TIME     
##               :287743                    :243411              :238978  
##  COUNTYWIDE   : 19680   4/27/2011 0:00:00:  1214   06:00:00 PM:  9802  
##  Countywide   :   993   5/25/2011 0:00:00:  1196   05:00:00 PM:  8314  
##  SPRINGFIELD  :   843   6/9/2011 0:00:00 :  1021   04:00:00 PM:  8104  
##  SOUTH PORTION:   810   4/4/2011 0:00:00 :  1007   12:00:00 PM:  7483  
##  NORTH PORTION:   784   5/30/2004 0:00:00:   998   11:59:00 PM:  7184  
##  (Other)      :591444   (Other)          :653450   (Other)    :622432  
##    COUNTY_END COUNTYENDN       END_RANGE           END_AZI      
##  Min.   :0    Mode:logical   Min.   :  0.0000          :724837  
##  1st Qu.:0    NA's:902297    1st Qu.:  0.0000   N      : 28082  
##  Median :0                   Median :  0.0000   S      : 22510  
##  Mean   :0                   Mean   :  0.9862   W      : 20119  
##  3rd Qu.:0                   3rd Qu.:  0.0000   E      : 20047  
##  Max.   :0                   Max.   :925.0000   NE     : 14606  
##                                                 (Other): 72096  
##            END_LOCATI         LENGTH              WIDTH         
##                 :499225   Min.   :   0.0000   Min.   :   0.000  
##  COUNTYWIDE     : 19731   1st Qu.:   0.0000   1st Qu.:   0.000  
##  SOUTH PORTION  :   833   Median :   0.0000   Median :   0.000  
##  NORTH PORTION  :   780   Mean   :   0.2301   Mean   :   7.503  
##  CENTRAL PORTION:   617   3rd Qu.:   0.0000   3rd Qu.:   0.000  
##  SPRINGFIELD    :   575   Max.   :2315.0000   Max.   :4400.000  
##  (Other)        :380536                                         
##        F               MAG            FATALITIES          INJURIES        
##  Min.   :0.0      Min.   :    0.0   Min.   :  0.0000   Min.   :   0.0000  
##  1st Qu.:0.0      1st Qu.:    0.0   1st Qu.:  0.0000   1st Qu.:   0.0000  
##  Median :1.0      Median :   50.0   Median :  0.0000   Median :   0.0000  
##  Mean   :0.9      Mean   :   46.9   Mean   :  0.0168   Mean   :   0.1557  
##  3rd Qu.:1.0      3rd Qu.:   75.0   3rd Qu.:  0.0000   3rd Qu.:   0.0000  
##  Max.   :5.0      Max.   :22000.0   Max.   :583.0000   Max.   :1700.0000  
##  NA's   :843563                                                           
##     PROPDMG          PROPDMGEXP        CROPDMG          CROPDMGEXP    
##  Min.   :   0.00          :465934   Min.   :  0.000          :618413  
##  1st Qu.:   0.00   K      :424665   1st Qu.:  0.000   K      :281832  
##  Median :   0.00   M      : 11330   Median :  0.000   M      :  1994  
##  Mean   :  12.06   0      :   216   Mean   :  1.527   k      :    21  
##  3rd Qu.:   0.50   B      :    40   3rd Qu.:  0.000   0      :    19  
##  Max.   :5000.00   5      :    28   Max.   :990.000   B      :     9  
##                    (Other):    84                     (Other):     9  
##       WFO                                       STATEOFFIC    
##         :142069                                      :248769  
##  OUN    : 17393   TEXAS, North                       : 12193  
##  JAN    : 13889   ARKANSAS, Central and North Central: 11738  
##  LWX    : 13174   IOWA, Central                      : 11345  
##  PHI    : 12551   KANSAS, Southwest                  : 11212  
##  TSA    : 12483   GEORGIA, North and Central         : 11120  
##  (Other):690738   (Other)                            :595920  
##                                                                                                                                                                                                     ZONENAMES     
##                                                                                                                                                                                                          :594029  
##                                                                                                                                                                                                          :205988  
##  GREATER RENO / CARSON CITY / M - GREATER RENO / CARSON CITY / M                                                                                                                                         :   639  
##  GREATER LAKE TAHOE AREA - GREATER LAKE TAHOE AREA                                                                                                                                                       :   592  
##  JEFFERSON - JEFFERSON                                                                                                                                                                                   :   303  
##  MADISON - MADISON                                                                                                                                                                                       :   302  
##  (Other)                                                                                                                                                                                                 :100444  
##     LATITUDE      LONGITUDE        LATITUDE_E     LONGITUDE_    
##  Min.   :   0   Min.   :-14451   Min.   :   0   Min.   :-14455  
##  1st Qu.:2802   1st Qu.:  7247   1st Qu.:   0   1st Qu.:     0  
##  Median :3540   Median :  8707   Median :   0   Median :     0  
##  Mean   :2875   Mean   :  6940   Mean   :1452   Mean   :  3509  
##  3rd Qu.:4019   3rd Qu.:  9605   3rd Qu.:3549   3rd Qu.:  8735  
##  Max.   :9706   Max.   : 17124   Max.   :9706   Max.   :106220  
##  NA's   :47                      NA's   :40                     
##                                            REMARKS           REFNUM      
##                                                :287433   Min.   :     1  
##                                                : 24013   1st Qu.:225575  
##  Trees down.\n                                 :  1110   Median :451149  
##  Several trees were blown down.\n              :   569   Mean   :451149  
##  Trees were downed.\n                          :   446   3rd Qu.:676723  
##  Large trees and power lines were blown down.\n:   432   Max.   :902297  
##  (Other)                                       :588294

Impact on Health

To evaluate the health impact, the total fatalities and the total injuries for each event type (EVTYPE) are calculated. The codes for this calculation are shown as follows.

Health_FATALITIES <- storm %>%
  select(EVTYPE, FATALITIES) %>%
  group_by(EVTYPE) %>%
  summarise(Total_Health_FATALITIS = sum(FATALITIES)) %>%
  arrange(- Total_Health_FATALITIS)

head(Health_FATALITIES, 10)
## # A tibble: 10 x 2
##    EVTYPE         Total_Health_FATALITIS
##    <fct>                           <dbl>
##  1 TORNADO                          5633
##  2 EXCESSIVE HEAT                   1903
##  3 FLASH FLOOD                       978
##  4 HEAT                              937
##  5 LIGHTNING                         816
##  6 TSTM WIND                         504
##  7 FLOOD                             470
##  8 RIP CURRENT                       368
##  9 HIGH WIND                         248
## 10 AVALANCHE                         224
Health_INJURIES <- storm %>%
  select(EVTYPE, INJURIES) %>%
  group_by(EVTYPE) %>%
  summarise(Total_Health_INJURIES = sum(INJURIES)) %>%
  arrange(- Total_Health_INJURIES)

head(Health_INJURIES, 10)
## # A tibble: 10 x 2
##    EVTYPE            Total_Health_INJURIES
##    <fct>                             <dbl>
##  1 TORNADO                           91346
##  2 TSTM WIND                          6957
##  3 FLOOD                              6789
##  4 EXCESSIVE HEAT                     6525
##  5 LIGHTNING                          5230
##  6 HEAT                               2100
##  7 ICE STORM                          1975
##  8 FLASH FLOOD                        1777
##  9 THUNDERSTORM WIND                  1488
## 10 HAIL                               1361

Impact on Economy

The data provides two types of economic impact, namely property damage (PROPDMG) and crop damage (CROPDMG). The actual damage in $USD is indicated by PROPDMGEXP and CROPDMGEXP parameters. According to this link, the index in the PROPDMGEXP and CROPDMGEXP can be interpreted as the following:-

  • H, h -> hundreds = x100
  • K, K -> kilos = x1,000
  • M, m -> millions = x1,000,000
  • B,b -> billions = x1,000,000,000
  • (+) -> x1
  • (-) -> x0
  • (?) -> x0
  • blank -> x0

The total damage caused by each event type is calculated with the following code.

damage <- storm %>% 
  select(EVTYPE, PROPDMG, PROPDMGEXP, CROPDMG, CROPDMGEXP)

icon <- sort(unique(as.character(damage$PROPDMGEXP)))
icon_multiplier  <- c(0,0,0,1,10,10,10,10,10,10,10,10,10,10^9,10^2,10^2,10^3,10^6,10^6)
multiplier <- data.frame(icon, icon_multiplier)

damage$Prop.Multiplier <- multiplier$icon_multiplier[match(damage$PROPDMGEXP, multiplier$icon)]
damage$Crop.Multiplier <- multiplier$icon_multiplier[match(damage$CROPDMGEXP, multiplier$icon)]

damage <- damage %>%
  mutate(Prop_DAMAGE = PROPDMG*Prop.Multiplier) %>%
  mutate(Crop_DAMAGE = CROPDMG*Crop.Multiplier) %>%
  mutate(TOTAL_DAMAGE = Prop_DAMAGE + Crop_DAMAGE)

damage_total <- damage %>%
  group_by(EVTYPE) %>%
  summarize(TOTAL_DAMAGE_EVTYPE = sum(TOTAL_DAMAGE)) %>%
  arrange(-TOTAL_DAMAGE_EVTYPE) 

head(damage_total,10)
## # A tibble: 10 x 2
##    EVTYPE            TOTAL_DAMAGE_EVTYPE
##    <fct>                           <dbl>
##  1 FLOOD                    150319678250
##  2 HURRICANE/TYPHOON         71913712800
##  3 TORNADO                   57352117607
##  4 STORM SURGE               43323541000
##  5 FLASH FLOOD               17562132111
##  6 DROUGHT                   15018672000
##  7 HURRICANE                 14610229010
##  8 RIVER FLOOD               10148404500
##  9 ICE STORM                  8967041810
## 10 TROPICAL STORM             8382236550

Results

Impact on Health

The top 10 events with the highest total fatalities and injuries are shown graphically.

ggplot(Health_FATALITIES[1:10,], 
       aes(x = reorder(EVTYPE, -Total_Health_FATALITIS), y = Total_Health_FATALITIS)) +
       geom_bar(stat = "identity", aes(fill = interaction(Total_Health_FATALITIS, EVTYPE))) + 
       theme(axis.text.x = element_text(angle=90, vjust=0.5, hjust=1), legend.position = 'none') + 
       ggtitle("Top 10 Events with Highest Total Fatalities") + 
       labs(x="EVENT TYPE", y="Total Fatalities")

ggplot(Health_INJURIES[1:10,],
       aes(x = reorder(EVTYPE, -Total_Health_INJURIES), y = Total_Health_INJURIES)) + 
       geom_bar(stat = "identity", aes(fill = interaction(Total_Health_INJURIES, EVTYPE))) + 
       theme(axis.text.x = element_text(angle=90, vjust=0.5, hjust=1), legend.position = 'none') + 
       ggtitle("Top 10 Events with Highest Total Injuries") + 
       labs(x="EVENT TYPE", y="Total Injuries")

Both figures shows that tornado causes the hightest damage on health. ### Impact on Economy

The top 10 events with the highest total economic damages (property and crop combined) are shown graphically.

ggplot(damage_total[1:10,], 
       aes(x = reorder(EVTYPE, -TOTAL_DAMAGE_EVTYPE), y = TOTAL_DAMAGE_EVTYPE)) + 
       geom_bar(stat="identity", aes(fill = interaction(TOTAL_DAMAGE_EVTYPE, EVTYPE))) + 
       theme(axis.text.x = element_text(angle=90, vjust=0.5, hjust=1), legend.position = 'none') + 
       ggtitle("Top 10 Events with Highest Economic Impact") + 
       labs(x="EVENT TYPE", y="Total Economic Impact ($USD)")

Above figure shows that flood has the highest economic impact.

Summary

From these data and graphs, we found that Tornado are most harmful with respect to population health, while Flood have the greatest economic consequences.