Synopsis

This research is meant to address 2 questions:

  1. Across the United States, which types of events are most harmful with respect to population health?
  2. Across the United States, which types of events have the greatest economic consequences?

This questions will be answered so that we can better prioritize natural disaster preparations.

Dependencies

library(ggplot2)
library(dplyr)

Data Processing

  1. Download data from [https://d396qusza40orc.cloudfront.net/repdata%2Fdata%2FStormData.csv.bz
  2. Import CSV into R
dt <- read.csv(bzfile("repdata_data_StormData.csv.bz2"))

Data Understanding

dim(dt)
## [1] 902297     37
head(dt, 1)
##   STATE__          BGN_DATE BGN_TIME TIME_ZONE COUNTY COUNTYNAME STATE
## 1       1 4/18/1950 0:00:00     0130       CST     97     MOBILE    AL
##    EVTYPE BGN_RANGE BGN_AZI BGN_LOCATI END_DATE END_TIME COUNTY_END
## 1 TORNADO         0                                               0
##   COUNTYENDN END_RANGE END_AZI END_LOCATI LENGTH WIDTH F MAG FATALITIES
## 1         NA         0                        14   100 3   0          0
##   INJURIES PROPDMG PROPDMGEXP CROPDMG CROPDMGEXP WFO STATEOFFIC ZONENAMES
## 1       15      25          K       0                                    
##   LATITUDE LONGITUDE LATITUDE_E LONGITUDE_ REMARKS REFNUM
## 1     3040      8812       3051       8806              1
summary(dt)
##     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              :   568   Mean   :451149  
##  Trees were downed.\n                          :   446   3rd Qu.:676723  
##  Large trees and power lines were blown down.\n:   432   Max.   :902297  
##  (Other)                                       :588295

The original idea was to calculate the severity of each natural disaster based on duration so that there is some reference to population exposure to said event. This is because a natural disaster with greater length will be more difficult to defend from. However, after seeing the summary of the dataframe, we see that END_DATE has 243,411 empty strings, and since that is about 30% of the database, time won’t be as reliable for reference.

Results

We will start by assigning a weight of 5x for fatalities, since we consider fatalitiews to be a more serious accident than injuries. After that, we just group the sum of the injuries and 5xfatalities by EVTYPE so we can see which event had more effect on human health.

library(dplyr)
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
library(ggplot2)
alfa <- data.frame(dt[,"FATALITIES"]*5)
colnames(alfa) <- c("WEIGHTED FATALITIES")
dt <- cbind(dt, alfa)

h_cost <- dt %>%
  group_by(EVTYPE) %>%
  summarise(FATALITIES_COST = sum(`WEIGHTED FATALITIES`), INJURIES_COST = sum(INJURIES)) %>%
  mutate(COST = FATALITIES_COST+INJURIES_COST) %>%
  arrange(desc(COST))

head(h_cost)
## Source: local data frame [6 x 4]
## 
##           EVTYPE FATALITIES_COST INJURIES_COST   COST
##           (fctr)           (dbl)         (dbl)  (dbl)
## 1        TORNADO           28165         91346 119511
## 2 EXCESSIVE HEAT            9515          6525  16040
## 3      TSTM WIND            2520          6957   9477
## 4      LIGHTNING            4080          5230   9310
## 5          FLOOD            2350          6789   9139
## 6           HEAT            4685          2100   6785
ggplot(head(h_cost, 10)) + 
  geom_point(aes(EVTYPE, COST), color=c("red"), shape=c(17), size=10) +
  geom_point(aes(EVTYPE, INJURIES_COST), color=c("blue"), shape=c(10), size=4) +
  geom_point(aes(EVTYPE, FATALITIES_COST), color=c("green"), shape=c(10), size=5)

We can clearly see that on the subject of health, the tornado is the most harmful by far. Perhaps for future research a good idea would be to map this damage on area, so we can pinpoint areas of opportunity since most tornadoes occur on tornado alley. On second place excessive heat could be an interesting problem to attack, since preparation is more passive and difficult to alocate. However, in this case, perhaps some research into time of the year where we find excessive heat to better prepare the population could be a future development.

Now, for economic consequences, we follow a similar path. However, here we have property damage and crop damage columns, which will be used to calculate economic cost of each disaster and map it in a similar way.

library(dplyr)
library(ggplot2)
e_cost <- dt %>%
  group_by(EVTYPE) %>%
  summarise(PROPERTY_DAMAGE = sum(PROPDMG), CROP_DAMAGE = sum(CROPDMG)) %>%
  mutate(COST = PROPERTY_DAMAGE+CROP_DAMAGE) %>%
  arrange(desc(COST))

head(e_cost)
## Source: local data frame [6 x 4]
## 
##              EVTYPE PROPERTY_DAMAGE CROP_DAMAGE      COST
##              (fctr)           (dbl)       (dbl)     (dbl)
## 1           TORNADO       3212258.2   100018.52 3312276.7
## 2       FLASH FLOOD       1420124.6   179200.46 1599325.1
## 3         TSTM WIND       1335965.6   109202.60 1445168.2
## 4              HAIL        688693.4   579596.28 1268289.7
## 5             FLOOD        899938.5   168037.88 1067976.4
## 6 THUNDERSTORM WIND        876844.2    66791.45  943635.6
ggplot(head(e_cost, 10)) + 
  geom_point(aes(EVTYPE, COST), color=c("red"), shape=c(17), size=10) +
  geom_point(aes(EVTYPE, PROPERTY_DAMAGE), color=c("yellow"), shape=c(10), size=4) +
  geom_point(aes(EVTYPE, CROP_DAMAGE), color=c("orange"), shape=c(10), size=4)

Once again, we find that tornado is by far the most dangerous natural disaster. However, here we find that flash flood is a major force in economic damage, being half of that of a tornado (in comparison to health cost, this is quite a lot). Perhaps an incidence mapping will help identify troublesome rivers and lakes, so as to better prepare the nearby settlements. Thunderstorm winds, flood, hail, and thunderstorms are also quite troublesome, and considering flash flood and flood have similar preparations, flood preparations should be quite relevant.