Synopsis

Among the several cause on economy and public health for communities and municipalities, storms and severe weather events are few of them. Here is an exploration of the US National Oceanic and Atmospheric Administration’s (NOAA) storm database. This database tracks characteristic of major storms and weather events in the US, including when and where they occur, which type of event, as well as the estimates of relevant fatalities, injuries and various forms of damage. It is deduced from the analysis that tornados result in maximum number of fatalities and injuries, floods result in maximum property damage, and Droughts cause maximum crop damage.

1. Data Processing

storm <- read.csv("repdata_data_StormData.csv",header=TRUE,sep=",")
summary(storm)
##     STATE__       BGN_DATE           BGN_TIME          TIME_ZONE        
##  Min.   : 1.0   Length:902297      Length:902297      Length:902297     
##  1st Qu.:19.0   Class :character   Class :character   Class :character  
##  Median :30.0   Mode  :character   Mode  :character   Mode  :character  
##  Mean   :31.2                                                           
##  3rd Qu.:45.0                                                           
##  Max.   :95.0                                                           
##                                                                         
##      COUNTY       COUNTYNAME           STATE              EVTYPE         
##  Min.   :  0.0   Length:902297      Length:902297      Length:902297     
##  1st Qu.: 31.0   Class :character   Class :character   Class :character  
##  Median : 75.0   Mode  :character   Mode  :character   Mode  :character  
##  Mean   :100.6                                                           
##  3rd Qu.:131.0                                                           
##  Max.   :873.0                                                           
##                                                                          
##    BGN_RANGE          BGN_AZI           BGN_LOCATI          END_DATE        
##  Min.   :   0.000   Length:902297      Length:902297      Length:902297     
##  1st Qu.:   0.000   Class :character   Class :character   Class :character  
##  Median :   0.000   Mode  :character   Mode  :character   Mode  :character  
##  Mean   :   1.484                                                           
##  3rd Qu.:   1.000                                                           
##  Max.   :3749.000                                                           
##                                                                             
##    END_TIME           COUNTY_END COUNTYENDN       END_RANGE       
##  Length:902297      Min.   :0    Mode:logical   Min.   :  0.0000  
##  Class :character   1st Qu.:0    NA's:902297    1st Qu.:  0.0000  
##  Mode  :character   Median :0                   Median :  0.0000  
##                     Mean   :0                   Mean   :  0.9862  
##                     3rd Qu.:0                   3rd Qu.:  0.0000  
##                     Max.   :0                   Max.   :925.0000  
##                                                                   
##    END_AZI           END_LOCATI            LENGTH              WIDTH         
##  Length:902297      Length:902297      Min.   :   0.0000   Min.   :   0.000  
##  Class :character   Class :character   1st Qu.:   0.0000   1st Qu.:   0.000  
##  Mode  :character   Mode  :character   Median :   0.0000   Median :   0.000  
##                                        Mean   :   0.2301   Mean   :   7.503  
##                                        3rd Qu.:   0.0000   3rd Qu.:   0.000  
##                                        Max.   :2315.0000   Max.   :4400.000  
##                                                                              
##        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   Length:902297      Min.   :  0.000   Length:902297     
##  1st Qu.:   0.00   Class :character   1st Qu.:  0.000   Class :character  
##  Median :   0.00   Mode  :character   Median :  0.000   Mode  :character  
##  Mean   :  12.06                      Mean   :  1.527                     
##  3rd Qu.:   0.50                      3rd Qu.:  0.000                     
##  Max.   :5000.00                      Max.   :990.000                     
##                                                                           
##      WFO             STATEOFFIC         ZONENAMES            LATITUDE   
##  Length:902297      Length:902297      Length:902297      Min.   :   0  
##  Class :character   Class :character   Class :character   1st Qu.:2802  
##  Mode  :character   Mode  :character   Mode  :character   Median :3540  
##                                                           Mean   :2875  
##                                                           3rd Qu.:4019  
##                                                           Max.   :9706  
##                                                           NA's   :47    
##    LONGITUDE        LATITUDE_E     LONGITUDE_       REMARKS         
##  Min.   :-14451   Min.   :   0   Min.   :-14455   Length:902297     
##  1st Qu.:  7247   1st Qu.:   0   1st Qu.:     0   Class :character  
##  Median :  8707   Median :   0   Median :     0   Mode  :character  
##  Mean   :  6940   Mean   :1452   Mean   :  3509                     
##  3rd Qu.:  9605   3rd Qu.:3549   3rd Qu.:  8735                     
##  Max.   : 17124   Max.   :9706   Max.   :106220                     
##                   NA's   :40                                        
##      REFNUM      
##  Min.   :     1  
##  1st Qu.:225575  
##  Median :451149  
##  Mean   :451149  
##  3rd Qu.:676723  
##  Max.   :902297  
## 
names(storm)
##  [1] "STATE__"    "BGN_DATE"   "BGN_TIME"   "TIME_ZONE"  "COUNTY"    
##  [6] "COUNTYNAME" "STATE"      "EVTYPE"     "BGN_RANGE"  "BGN_AZI"   
## [11] "BGN_LOCATI" "END_DATE"   "END_TIME"   "COUNTY_END" "COUNTYENDN"
## [16] "END_RANGE"  "END_AZI"    "END_LOCATI" "LENGTH"     "WIDTH"     
## [21] "F"          "MAG"        "FATALITIES" "INJURIES"   "PROPDMG"   
## [26] "PROPDMGEXP" "CROPDMG"    "CROPDMGEXP" "WFO"        "STATEOFFIC"
## [31] "ZONENAMES"  "LATITUDE"   "LONGITUDE"  "LATITUDE_E" "LONGITUDE_"
## [36] "REMARKS"    "REFNUM"

2. Results

Q. 1. Across the United States, which types of events (as indicated in the EVTYPE variable) are most harmful with respect to population health?

2.1. Extracting the useful data

The dataset consists of a lot of variables (columns) which are not required for the current analysis. Therefore, we are considering the project relevant variables (columns).

variables<-c("EVTYPE","FATALITIES","INJURIES","PROPDMG", "PROPDMGEXP","CROPDMG","CROPDMGEXP")
stormdata<-storm[variables]

dim(stormdata)
## [1] 902297      7
names(stormdata)
## [1] "EVTYPE"     "FATALITIES" "INJURIES"   "PROPDMG"    "PROPDMGEXP"
## [6] "CROPDMG"    "CROPDMGEXP"

Top ten events that cause most fatalities.

## Procedure = aggregate,  the top 10 fatalities by the event type and sort the output in descending order

Fatalities <- aggregate(FATALITIES ~ EVTYPE, data = stormdata, FUN = sum)
Top10_Fatalities <- Fatalities[order(-Fatalities$FATALITIES), ][1:10, ] 
Top10_Fatalities 
##             EVTYPE FATALITIES
## 834        TORNADO       5633
## 130 EXCESSIVE HEAT       1903
## 153    FLASH FLOOD        978
## 275           HEAT        937
## 464      LIGHTNING        816
## 856      TSTM WIND        504
## 170          FLOOD        470
## 585    RIP CURRENT        368
## 359      HIGH WIND        248
## 19       AVALANCHE        224

Events that cause the most injuries Top-10 by Weather Event.

# Procedure = aggregate, top 10 injuries by the event type and sort the output in descending order

Injuries <- aggregate(INJURIES ~ EVTYPE, data = stormdata, FUN = sum)
Top10_Injuries <- Injuries[order(-Injuries$INJURIES), ][1:10, ] 
Top10_Injuries 
##                EVTYPE INJURIES
## 834           TORNADO    91346
## 856         TSTM WIND     6957
## 170             FLOOD     6789
## 130    EXCESSIVE HEAT     6525
## 464         LIGHTNING     5230
## 275              HEAT     2100
## 427         ICE STORM     1975
## 153       FLASH FLOOD     1777
## 760 THUNDERSTORM WIND     1488
## 244              HAIL     1361

Plotting Top 10 Fatalities & Injuries for Weather Event Types ( Population Health Impact )

# Procedure = plot graphs showing the top 10 fatalities and injuries

par(mfrow=c(1,2),mar=c(10,3,3,2))
barplot(Top10_Fatalities$FATALITIES,names.arg=Top10_Fatalities$EVTYPE,las=3,col="tomato",ylab="fatalities",main="Top 10 fatalities")
barplot(Top10_Injuries$INJURIES,names.arg=Top10_Injuries$EVTYPE,las=3,col="sienna1",ylab="injuries",main="Top 10 Injuries")

Figure 1: Top 10 event responsible for highest number of fatalities and injuries.

Q. 2. Across the United States, which types of events have the greatest economic consequences?

An analysis of the weather events responsible for the greatest economic consequences. Hypothesis: Economic consequences means damages. The two significant types of damage typically caused by weather events include ‘properties and crops’

Upon reviewing the column names, the property damage(PROPDMG) and crop damage(CROPDMG) columns both have another related column titled ‘exponents’ (i.e - PROPDMGEXP and CROPDMGEXP respectively). As a result, let’s convert the exponent columns into numeric data for the calculation of total property and crop damages encountered.

Property damage exponents for each level listed out & assigned those values for the property exponent data. Invalid data was excluded by assigning the value as ‘0’. Then, the property damage value was calculated by multiplying the property damage and property exponent value.

unique(stormdata$PROPDMGEXP)
##  [1] "K" "M" ""  "B" "m" "+" "0" "5" "6" "?" "4" "2" "3" "h" "7" "H" "-" "1" "8"
# Assigning values for the property exponent stormdata 
stormdata$PROPEXP[stormdata$PROPDMGEXP == "K"] <- 1000
stormdata$PROPEXP[stormdata$PROPDMGEXP == "M"] <- 1e+06
stormdata$PROPEXP[stormdata$PROPDMGEXP == ""] <- 1
stormdata$PROPEXP[stormdata$PROPDMGEXP == "B"] <- 1e+09
stormdata$PROPEXP[stormdata$PROPDMGEXP == "m"] <- 1e+06
stormdata$PROPEXP[stormdata$PROPDMGEXP == "0"] <- 1
stormdata$PROPEXP[stormdata$PROPDMGEXP == "5"] <- 1e+05
stormdata$PROPEXP[stormdata$PROPDMGEXP == "6"] <- 1e+06
stormdata$PROPEXP[stormdata$PROPDMGEXP == "4"] <- 10000
stormdata$PROPEXP[stormdata$PROPDMGEXP == "2"] <- 100
stormdata$PROPEXP[stormdata$PROPDMGEXP == "3"] <- 1000
stormdata$PROPEXP[stormdata$PROPDMGEXP == "h"] <- 100
stormdata$PROPEXP[stormdata$PROPDMGEXP == "7"] <- 1e+07
stormdata$PROPEXP[stormdata$PROPDMGEXP == "H"] <- 100
stormdata$PROPEXP[stormdata$PROPDMGEXP == "1"] <- 10
stormdata$PROPEXP[stormdata$PROPDMGEXP == "8"] <- 1e+08

# Assigning '0' to invalid exponent stormdata
stormdata$PROPEXP[stormdata$PROPDMGEXP == "+"] <- 0
stormdata$PROPEXP[stormdata$PROPDMGEXP == "-"] <- 0
stormdata$PROPEXP[stormdata$PROPDMGEXP == "?"] <- 0

# Calculating the property damage value
stormdata$PROPDMGVAL <- stormdata$PROPDMG * stormdata$PROPEXP

# Defining & Calculating [ Crop Damage ]

# Crop damage exponents for each level listed out & assigned those values for the crop exponent data. 
# Invalid data was excluded by assigning the value as '0'. 
# Then, the crop damage value was calculated by multiplying the crop damage and crop exponent value.

unique(stormdata$CROPDMGEXP)
## [1] ""  "M" "K" "m" "B" "?" "0" "k" "2"
# Assigning values for the crop exponent stormdata 
stormdata$CROPEXP[stormdata$CROPDMGEXP == "M"] <- 1e+06
stormdata$CROPEXP[stormdata$CROPDMGEXP == "K"] <- 1000
stormdata$CROPEXP[stormdata$CROPDMGEXP == "m"] <- 1e+06
stormdata$CROPEXP[stormdata$CROPDMGEXP == "B"] <- 1e+09
stormdata$CROPEXP[stormdata$CROPDMGEXP == "0"] <- 1
stormdata$CROPEXP[stormdata$CROPDMGEXP == "k"] <- 1000
stormdata$CROPEXP[stormdata$CROPDMGEXP == "2"] <- 100
stormdata$CROPEXP[stormdata$CROPDMGEXP == ""] <- 1

# Assigning '0' to invalid exponent stormdata
stormdata$CROPEXP[stormdata$CROPDMGEXP == "?"] <- 0

# calculating the crop damage 
stormdata$CROPDMGVAL <- stormdata$CROPDMG * stormdata$CROPEXP

# Property Damage Summary

# Procedure = aggregate the property damage by the event type and sort the output it in descending order

prop <- aggregate(PROPDMGVAL~EVTYPE,data=stormdata,FUN=sum,na.rm=TRUE)
prop <- prop[with(prop,order(-PROPDMGVAL)),]
prop <- head(prop,10)
print(prop)
##                EVTYPE   PROPDMGVAL
## 170             FLOOD 144657709807
## 411 HURRICANE/TYPHOON  69305840000
## 834           TORNADO  56947380617
## 670       STORM SURGE  43323536000
## 153       FLASH FLOOD  16822673979
## 244              HAIL  15735267513
## 402         HURRICANE  11868319010
## 848    TROPICAL STORM   7703890550
## 972      WINTER STORM   6688497251
## 359         HIGH WIND   5270046260
# Crop Damage Summary

# Procedure = aggregate the crop damage by the event type and sort the output it in descending order

crop <- aggregate(CROPDMGVAL~EVTYPE,data=stormdata,FUN=sum,na.rm=TRUE)
crop <- crop[with(crop,order(-CROPDMGVAL)),]
crop <- head(crop,10)
print(crop)
##                EVTYPE  CROPDMGVAL
## 95            DROUGHT 13972566000
## 170             FLOOD  5661968450
## 590       RIVER FLOOD  5029459000
## 427         ICE STORM  5022113500
## 244              HAIL  3025954473
## 402         HURRICANE  2741910000
## 411 HURRICANE/TYPHOON  2607872800
## 153       FLASH FLOOD  1421317100
## 140      EXTREME COLD  1292973000
## 212      FROST/FREEZE  1094086000
# Plot of Top 10 Property & Crop damages by Weather Event Types ( Economic Consequences )

# plot the graph showing the top 10 property and crop damages

par(mfrow=c(1,2),mar=c(11,3,3,2))
barplot(prop$PROPDMGVAL/(10^9),names.arg=prop$EVTYPE,las=2,col="firebrick1",ylab="Prop.damage(billions)",main="Top10 Prop.Damages")
barplot(crop$CROPDMGVAL/(10^9),names.arg=crop$EVTYPE,las=2,col="firebrick1",ylab="Crop damage(billions)",main="Top10 Crop.Damages")

Figure 2: Top 10 events causing the highest economic damage.

3. Conclusion

  1. Highest number of fatalities and injuries occurred due to Tornado, followed by Excessive Heat and Thunderstorm.

  2. Maximum property damage is done by Floods, while Droughts cause maximum crop damage. Second major events that caused the maximum damage was Hurricanes/Typhoon for property damage and Floods for crop damage.