Synopsis

In this analysis we utilize the NOAA storm database to find the meteorological phenomena that causes more human and economical damage. Our analysis groups data with respect to the event type (i.e. flood) so that we are able to identify the event type that is more dangerous for humans or economical damage. We further divide our results for human damage in fatalities and injuries related to the event type. In the case of economical costs, we separate our results in properties and crops with respect to the event type. Our results show that the event that causes more human damages are tornadoes for both fatalities and injuries. In the case of economical costs tornadoes have higher impact on property while hail affects crops with higher intensity.

Processing

Our storm data file was read with the “read.csv” command. We used the “dplyr” and the “gridExtra” libraries to facilitate our processing step when we group and summarize data (with dplyr commands) and to print nice tables (with gridExtra).

This can be seen in the following code chunk.

    library("dplyr")
    library("gridExtra")

This is a summary of the storm database provided by the National Oceanic and Atmospheric Administration (NOAA). It contains a total of 902,297 storm related events with 37 variables describing each of them. Although there are 37 variables in the database, we only use 5 of them for this study. These are:

  • EVTYPE, the type of event (WE USE THIS VARIABLE IN OUR ANALYSIS to separate the damages by the types of event)
  • FATALITIES, number of fatalities produced by the event
  • INJURIES, number of injured people
  • PROPDMG, cost of property damages
  • CROPDMG, cost of crop damages

A summary of the storm dataset is presented as follows:

    storm <- read.csv(bzfile('./data/repdata-data-StormData.csv.bz2'))
    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              :   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

In order to summarize our results with respect to the event type, we grouped the event data by type of event and then, for each of our analyzes, we summarized our data with respect to fatalities (FATALITIES), injuries (INJURIES), property damage (PROPDMG), and crop damage (CROPDMG) respectively. Finaly, we ordered the data produced by our summary in descending order to identify the events that caused the highest damage. We divided the main values by 1000 in order to obtain smaller values and express them in thousands (i.e. thousands of injuries).

This was performed with the following code:

    storm_by_event <- group_by(storm, EVTYPE)

    sum_fatalities <- summarise(storm_by_event, FATALITIES = sum(FATALITIES)/1000)
    sum_fatalities <- sum_fatalities[with(sum_fatalities, order(-FATALITIES)),]
    sum_injuries   <- summarise(storm_by_event, INJURIES = sum(INJURIES)/1000)
    sum_injuries   <- sum_injuries[with(sum_injuries, order(-INJURIES)),]
   
    sum_propdmg    <- summarise(storm_by_event, PROPDMG = sum(PROPDMG)/1000)
    sum_propdmg    <- sum_propdmg[with(sum_propdmg, order(-PROPDMG)),]
    sum_cropdmg    <- summarise(storm_by_event, CROPDMG = sum(CROPDMG)/1000)
    sum_cropdmg    <- sum_cropdmg[with(sum_cropdmg, order(-CROPDMG)),]

Results

Results from our data analysis over the NOAA storms dataset show that tornadoes are the event type that causes more damage to humans, for both, fatalities (5,600 people) and injuries (91,300 people). We also found that tornadoes are the event type that causes more costs related to properties (3,200,000 dollars) and hail for crops (579,000 dollars). We can observe these results in figure 1. Note that values are expressed in thousands. We can also see that there is high overlap in the types of events for fatalities, injuries, and property damage. We found smaller overlap (but still significant) with the events related to crop damages.

    par(mfrow=c(4,1),mar=c(2,8,3,0))
    m <- barplot(sum_fatalities$FATALITIES[1:5], las=1, main="Fatalities per Type of Event")
    axis(1, at=m, labels=sum_fatalities$EVTYPE[1:5], las=1)

    m <- barplot(sum_injuries$INJURIES[1:5], las=1, main="Injuries per Type of Event")
    axis(1, at=m, labels=sum_injuries$EVTYPE[1:5], las=1)

    m <- barplot(sum_propdmg$PROPDMG[1:5], las=1, main="Property Costs per Type of Event")
    axis(1, at=m, labels=sum_propdmg$EVTYPE[1:5], las=1)

    m <- barplot(sum_cropdmg$CROPDMG[1:5], las=1, main="Crop Costs per Type of Event")
    axis(1, at=m, labels=sum_cropdmg$EVTYPE[1:5], las=1)
Figure 1. Human Fatalities, Human Injuries, Property Costs, and Crops Costs Impact Caused by Storm Events. Values are expressed in thousands.

Figure 1. Human Fatalities, Human Injuries, Property Costs, and Crops Costs Impact Caused by Storm Events. Values are expressed in thousands.

The most harmful event types for humans fatalities are

  1. TORNADO
  2. EXCESSIVE HEAT
  3. FLASH FLOOD
  4. HEAT
  5. LIGHTNING

The most harmful event types for humans injuries are

  1. TORNADO
  2. TSTM WIND
  3. FLOOD
  4. EXCESSIVE HEAT
  5. LIGHTNING

The most harmful event types for economical cost of properties are

  1. TORNADO
  2. FLASH FLOOD
  3. TSTM WIND
  4. FLOOD
  5. THUNDERSTORM WIND

The most harmful event types for economical cost of crops are

  1. HAIL
  2. FLASH FLOOD
  3. FLOOD
  4. TSTM WIND
  5. TORNADO

According to these results, government should give priority to prevent damage from tornadoes, hail, floods, heat, flash floods, lightning, thunder storm, and tstm wind. Other events are also important but these are a priority.

Below we present tables showing the first 10 types of events that cause more damage to humans (for fatalities and injuries) and to properties and crops (for cost of damages).

Table 1. The 10 disasters that are more harmful for people with respect to fatalities:

    grid.table(sum_fatalities[1:10,],gp=gpar(fontsize=8))

Table 2. The 10 disasters that are more harmful for people with respect to injuries:

    grid.table(sum_injuries[1:10,],gp=gpar(fontsize=8))

Table 3. The 10 event types with more economical consequences on properties:

    grid.table(sum_propdmg[1:10,],gp=gpar(fontsize=8))

Table 4. The 10 event types with more economical consequences on crops:

    grid.table(sum_cropdmg[1:10,],gp=gpar(fontsize=8))