Analysis of Severe Weather Events Impact on Population Health & Economy

Synopsis

This report is for the peer assessment 2 for Reproducible Research on Coursera.

The task is to analyze the StormData data set and address the question of which types of weather events are most harmful to population health & economic impact.

The conclusion of the analysis is that tornado's are most harmful to population health (fatalities & injuries) and tornado, storm & wind have the greatest economic impact (damages to property & crop).

Data Processing

Download the data and load the raw csv file.

src <- "StormData.csv"
if (!file.exists(src)){
  download.file("https://d396qusza40orc.cloudfront.net/repdata%2Fdata%2FStormData.csv.bz2", "StormData.csv.bz2", method="curl")
  bunzip2("StormData.csv.bz2", overwrite=T, remove=F)
}

data <- read.csv(src)
names(data)

##  [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"

Subset the data by weather event type and aggregate by population health & economic impact.

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

# subset data
data <- data[, c("EVTYPE","FATALITIES","INJURIES","PROPDMG","CROPDMG")]

# events are most harmful to population health
data.health <- aggregate(cbind(FATALITIES, INJURIES) ~ EVTYPE, data, sum, rm.na=TRUE)
#data.health$y <- rowSums(data.health[, c(2, 3)])
data.health$sum <- data.health$FATALITIES+data.health$INJURIES
data.health <- data.health[order(-data.health$sum),]
data.health <- head(data.health, 10)

Across the United States, which types of events have the greatest economic consequence?

# events have the greatest economic consequences
data.economic <- aggregate(cbind(PROPDMG, CROPDMG) ~ EVTYPE, data, sum, rm.na=TRUE)
data.economic$sum <- data.economic$PROPDMG+data.economic$CROPDMG
data.economic <- data.economic[order(-data.economic$sum),]
data.economic <- head(data.economic, 10)

Results

Most harmful severe weather events for population health

barplot(data.health$sum,
        las=3,
        names.arg = data.health$EVTYPE,
        main = "Top 10 Most Harmful Weather Events",
        ylab = "Number of fatalities & injuries",
        col = "red")

The graph above shows that tornado’s has the greatest impact on population health.

Weather events with the greatest economic impact

barplot(data.economic$sum,
        las=3,
        names.arg = data.economic$EVTYPE,
        main = "Top 10 Weather Events With Highest Economic Impact",
        ylab = "Property & crop damages",
        col = "blue")

The graph above shows that tornado, flood & wind has the greatest economic impact on property & crop damages.