Synopsis

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.

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.

This data analysis will address the following questions:

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

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

Loading and Processing the Data

The Storm Data is obtained from the U.S. National Oceanic and Atmospheric Administration’s (NOAA) Storm Database.

The file is a Comma Separated Value (.csv) format, so we read it with the specific function read.csv().

stormData <- read.csv("repdata_data_StormData.csv")

Preview the data

head(stormData)
##   STATE__           BGN_DATE BGN_TIME TIME_ZONE COUNTY COUNTYNAME STATE
## 1       1  4/18/1950 0:00:00     0130       CST     97     MOBILE    AL
## 2       1  4/18/1950 0:00:00     0145       CST      3    BALDWIN    AL
## 3       1  2/20/1951 0:00:00     1600       CST     57    FAYETTE    AL
## 4       1   6/8/1951 0:00:00     0900       CST     89    MADISON    AL
## 5       1 11/15/1951 0:00:00     1500       CST     43    CULLMAN    AL
## 6       1 11/15/1951 0:00:00     2000       CST     77 LAUDERDALE    AL
##    EVTYPE BGN_RANGE BGN_AZI BGN_LOCATI END_DATE END_TIME COUNTY_END
## 1 TORNADO         0                                               0
## 2 TORNADO         0                                               0
## 3 TORNADO         0                                               0
## 4 TORNADO         0                                               0
## 5 TORNADO         0                                               0
## 6 TORNADO         0                                               0
##   COUNTYENDN END_RANGE END_AZI END_LOCATI LENGTH WIDTH F MAG FATALITIES
## 1         NA         0                      14.0   100 3   0          0
## 2         NA         0                       2.0   150 2   0          0
## 3         NA         0                       0.1   123 2   0          0
## 4         NA         0                       0.0   100 2   0          0
## 5         NA         0                       0.0   150 2   0          0
## 6         NA         0                       1.5   177 2   0          0
##   INJURIES PROPDMG PROPDMGEXP CROPDMG CROPDMGEXP WFO STATEOFFIC ZONENAMES
## 1       15    25.0          K       0                                    
## 2        0     2.5          K       0                                    
## 3        2    25.0          K       0                                    
## 4        2     2.5          K       0                                    
## 5        2     2.5          K       0                                    
## 6        6     2.5          K       0                                    
##   LATITUDE LONGITUDE LATITUDE_E LONGITUDE_ REMARKS REFNUM
## 1     3040      8812       3051       8806              1
## 2     3042      8755          0          0              2
## 3     3340      8742          0          0              3
## 4     3458      8626          0          0              4
## 5     3412      8642          0          0              5
## 6     3450      8748          0          0              6

Processing data for question 1

To see which events are the most harmful with respect to population health we need to aggregate() the data per event and do the sum of fatalities in one column and injuries in another column.

maxHarmEv <- aggregate(x = list(FATALITIES = stormData$FATALITIES, 
                                INJURIES = stormData$INJURIES), 
                       by = list(EVENT = stormData$EVTYPE), 
                       FUN = sum)

We can also remove the events with zero values in the FATALITIES and INJURIES column.

maxHarmEv <- maxHarmEv[maxHarmEv$FATALITIES + maxHarmEv$INJURIES != 0, ]
head(maxHarmEv)
##           EVENT FATALITIES INJURIES
## 18     AVALANCE          1        0
## 19    AVALANCHE        224      170
## 29    BLACK ICE          1       24
## 30     BLIZZARD        101      805
## 42 blowing snow          1        1
## 44 BLOWING SNOW          1       13

Let’s see now a brief summary of the data for fatalities and injuries of the events that have caused at least one dead or injured.

summary(maxHarmEv$FATALITIES)
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##    0.00    1.00    2.00   68.84   10.25 5633.00
summary(maxHarmEv$INJURIES)
##     Min.  1st Qu.   Median     Mean  3rd Qu.     Max. 
##     0.00     0.00     2.00   638.80    35.25 91350.00

To show the most harmful events with respect to population health I decided to subset again the data removing the events with fatalities or injuries smaller than the respective mean (68.84 for fatalities and 638.80 for injuries).

fataData <- maxHarmEv[maxHarmEv$FATALITIES >= mean(maxHarmEv$FATALITIES), 1:2]
injuData <- maxHarmEv[maxHarmEv$INJURIES >= mean(maxHarmEv$INJURIES), c(1,3)]

And we sort the data in descending order.

fataData <- fataData[order(-fataData$FATALITIES), ]
injuData <- injuData[order(-injuData$INJURIES), ]

The data is ready, the result will be exposed in the next section. Now we are going to elaborate the data to understand which types of events have the greatest economic consequences.

Processing data for question 2

Damages are divided in two categories: damages to properties and damages to crops.

For properties there are two important column PROPDMG and PROPDMGEXP. The first one is in dollar unit, the second one has three values: “K” for thousands, “M” for millions, and “B” for billions. We decided to multiply the first column for the respective unit.

econDmg <- stormData

econDmg <- econDmg[, which(names(econDmg) %in% c("EVTYPE", "PROPDMG", "PROPDMGEXP", "CROPDMG", "CROPDMGEXP"))]

econDmg[econDmg$PROPDMGEXP == "K", ]$PROPDMG = 
        econDmg[econDmg$PROPDMGEXP == "K", ]$PROPDMG * 10^3

econDmg[econDmg$PROPDMGEXP == "M", ]$PROPDMG = 
        econDmg[econDmg$PROPDMGEXP == "M", ]$PROPDMG * 10^6

econDmg[econDmg$PROPDMGEXP == "B", ]$PROPDMG = 
        econDmg[econDmg$PROPDMGEXP == "B", ]$PROPDMG * 10^9

The same is apply to the crop damages, in this case the relevant columns are CROPDMG and CROPDMGEXP.

econDmg[econDmg$CROPDMGEXP == "K", ]$CROPDMG = 
        econDmg[econDmg$CROPDMGEXP == "K", ]$CROPDMG * 10^3

econDmg[econDmg$CROPDMGEXP == "M", ]$CROPDMG = 
        econDmg[econDmg$CROPDMGEXP == "M", ]$CROPDMG * 10^6

econDmg[econDmg$CROPDMGEXP == "B", ]$CROPDMG = 
        econDmg[econDmg$CROPDMGEXP == "B", ]$CROPDMG * 10^9

To obtain the total damage we aggregate the datasets and we do the sum of the crop damages and property damages.

econDmg <- aggregate(x = list(TOTDMG = econDmg$PROPDMG + econDmg$CROPDMG), 
                     by = list(EVENT = econDmg$EVTYPE), 
                     FUN = sum)

We can also remove the values equal to zero.

econDmg <- econDmg[econDmg$TOTDMG != 0, ]

Based on the method we applied earlier, we are going to expose a brief summary and we are going to subset the events that caused a damage bigger than the mean value.

summary(econDmg$TOTDMG)
##      Min.   1st Qu.    Median      Mean   3rd Qu.      Max. 
## 0.000e+00 1.500e+04 2.215e+05 1.105e+09 6.188e+06 1.503e+11
econDmg <- econDmg[econDmg$TOTDMG >= mean(econDmg$TOTDMG), ]

And now we sort the data in descending order.

econDmg <- econDmg[order(-econDmg$TOTDMG), ]

Results

After the elaboration of the data we are going to expose our result with a barplot.

par(mfrow = c(1, 2), mai = c(1.4, 0.5, 0.5, 0))

fataPlot <- with(fataData, barplot(FATALITIES, names.arg = EVENT, axisnames = FALSE, col = rgb(0,0,1,1/4)))
text(fataPlot, par("usr")[3], labels = fataData$EVENT, srt=60, adj = 1, xpd = TRUE, cex = 0.65)

injuPlot <- with(injuData, barplot(INJURIES, names.arg = EVENT, axisnames = FALSE, col = rgb(1,0,1,1/4)))
text(injuPlot, par("usr")[3], labels = injuData$EVENT, srt=60, adj = 1, xpd = TRUE, cex = 0.65)

title("Most Harmful Events", outer = TRUE, line = -1)
legend("topright", legend = c("Fatalities","Injuries"), 
       col = c(rgb(0,0,1,1/4), rgb(1,0,0,1/4)), 
       pch = 19, cex = 0.8)

For completeness, below it is shown the first 6 harmful events for fatalities.

head(fataData)
##              EVENT FATALITIES
## 834        TORNADO       5633
## 130 EXCESSIVE HEAT       1903
## 153    FLASH FLOOD        978
## 275           HEAT        937
## 464      LIGHTNING        816
## 856      TSTM WIND        504

And for injuries.

head(injuData)
##              EVENT INJURIES
## 834        TORNADO    91346
## 856      TSTM WIND     6957
## 170          FLOOD     6789
## 130 EXCESSIVE HEAT     6525
## 464      LIGHTNING     5230
## 275           HEAT     2100

In both cases, the TORNADO event has been the most harmful with respect to population health.

Concerning the damages we can plot just one graph. This because earlier we aggregated the data doing the sum of damages on properties and crops, as they have the same unit of measure ($).

par(mai = c(1.6, 1, 0.5, 0))
econDmgPlot <- with(econDmg, barplot(TOTDMG, names.arg = EVENT, axisnames = FALSE, 
                                     col = rgb(0,1,0,1/4), ylab = "Damage in $", font.lab = 2))
text(econDmgPlot, par("usr")[3], labels = econDmg$EVENT, srt=60, adj = 1, xpd = TRUE, cex = 0.65)

title("Total Damage (Properties and Crops)", outer = TRUE, line = -1)

For completeness, below it is shown the first 6 events that caused biggest damages.

head(econDmg)
##                 EVENT       TOTDMG
## 170             FLOOD 150319678257
## 411 HURRICANE/TYPHOON  71913712800
## 834           TORNADO  57340614060
## 670       STORM SURGE  43323541000
## 244              HAIL  18752904943
## 153       FLASH FLOOD  17562129167

We can clearly see that the FLOOD event is the one that caused biggest dollars of damage.