Synopsis

In this brief report we analize the effects of severe weather events in the US for the period of 1950 to 2011, using the National Oceanic and Atmospheric Administration’s (NOAA) storm database. The focus is on the effects of the severe weather events in the population health, approximated by the number of fatalitis and injures, and the economic effects, measure by property and crop damages. We selected the top ten most harmful events by health and economic effects.

Data Processing

Loading of libraries used for the analysis.

library(tidyverse)
## Warning: package 'tidyverse' was built under R version 3.6.3
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## v tibble  3.0.1     v dplyr   0.8.3
## v tidyr   1.0.2     v stringr 1.4.0
## v readr   1.3.1     v forcats 0.5.0
## Warning: package 'ggplot2' was built under R version 3.6.3
## Warning: package 'tibble' was built under R version 3.6.3
## Warning: package 'tidyr' was built under R version 3.6.3
## Warning: package 'forcats' was built under R version 3.6.3
## -- Conflicts ----------------------------------------------------------------------------------------------------------------------------------- tidyverse_conflicts() --
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()
library(ggplot2)

Reading the data to the working environment.

data_noaa <- read.csv(bzfile("repdata_data_StormData.csv.bz2"),header = TRUE)

Exploring of the data.

str(data_noaa)
## 'data.frame':    902297 obs. of  37 variables:
##  $ STATE__   : num  1 1 1 1 1 1 1 1 1 1 ...
##  $ BGN_DATE  : Factor w/ 16335 levels "1/1/1966 0:00:00",..: 6523 6523 4242 11116 2224 2224 2260 383 3980 3980 ...
##  $ BGN_TIME  : Factor w/ 3608 levels "00:00:00 AM",..: 272 287 2705 1683 2584 3186 242 1683 3186 3186 ...
##  $ TIME_ZONE : Factor w/ 22 levels "ADT","AKS","AST",..: 7 7 7 7 7 7 7 7 7 7 ...
##  $ COUNTY    : num  97 3 57 89 43 77 9 123 125 57 ...
##  $ COUNTYNAME: Factor w/ 29601 levels "","5NM E OF MACKINAC BRIDGE TO PRESQUE ISLE LT MI",..: 13513 1873 4598 10592 4372 10094 1973 23873 24418 4598 ...
##  $ STATE     : Factor w/ 72 levels "AK","AL","AM",..: 2 2 2 2 2 2 2 2 2 2 ...
##  $ EVTYPE    : Factor w/ 985 levels "   HIGH SURF ADVISORY",..: 834 834 834 834 834 834 834 834 834 834 ...
##  $ BGN_RANGE : num  0 0 0 0 0 0 0 0 0 0 ...
##  $ BGN_AZI   : Factor w/ 35 levels "","  N"," NW",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ BGN_LOCATI: Factor w/ 54429 levels "","- 1 N Albion",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ END_DATE  : Factor w/ 6663 levels "","1/1/1993 0:00:00",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ END_TIME  : Factor w/ 3647 levels ""," 0900CST",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ COUNTY_END: num  0 0 0 0 0 0 0 0 0 0 ...
##  $ COUNTYENDN: logi  NA NA NA NA NA NA ...
##  $ END_RANGE : num  0 0 0 0 0 0 0 0 0 0 ...
##  $ END_AZI   : Factor w/ 24 levels "","E","ENE","ESE",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ END_LOCATI: Factor w/ 34506 levels "","- .5 NNW",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ LENGTH    : num  14 2 0.1 0 0 1.5 1.5 0 3.3 2.3 ...
##  $ WIDTH     : num  100 150 123 100 150 177 33 33 100 100 ...
##  $ F         : int  3 2 2 2 2 2 2 1 3 3 ...
##  $ MAG       : num  0 0 0 0 0 0 0 0 0 0 ...
##  $ FATALITIES: num  0 0 0 0 0 0 0 0 1 0 ...
##  $ INJURIES  : num  15 0 2 2 2 6 1 0 14 0 ...
##  $ PROPDMG   : num  25 2.5 25 2.5 2.5 2.5 2.5 2.5 25 25 ...
##  $ PROPDMGEXP: Factor w/ 19 levels "","-","?","+",..: 17 17 17 17 17 17 17 17 17 17 ...
##  $ CROPDMG   : num  0 0 0 0 0 0 0 0 0 0 ...
##  $ CROPDMGEXP: Factor w/ 9 levels "","?","0","2",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ WFO       : Factor w/ 542 levels ""," CI","$AC",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ STATEOFFIC: Factor w/ 250 levels "","ALABAMA, Central",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ ZONENAMES : Factor w/ 25112 levels "","                                                                                                               "| __truncated__,..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ LATITUDE  : num  3040 3042 3340 3458 3412 ...
##  $ LONGITUDE : num  8812 8755 8742 8626 8642 ...
##  $ LATITUDE_E: num  3051 0 0 0 0 ...
##  $ LONGITUDE_: num  8806 0 0 0 0 ...
##  $ REMARKS   : Factor w/ 436781 levels "","-2 at Deer Park\n",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ REFNUM    : num  1 2 3 4 5 6 7 8 9 10 ...
summary(data_noaa)
##     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 variables needed to answer the main questions are the following: EVTYPE FATALITIES INJURIES PROPDMG PROPDMGEXP CROPDMG *CROPDMGEXP

Also, to compare the economic consequences, we need to standarized the measurement of the monetary ammounts. Acording to the documentation, the variables PROPDMGEXP y CROPDMGEXP identify the magnitude acording to the letters “K” for thousands, “M” for millions, and “B” for billions. We assume the other cases do not correspond to valid measurements and will not be considered.

#Variables of interest
data_noaa_subset <- subset(data_noaa, select = c(EVTYPE, FATALITIES, INJURIES, PROPDMG, PROPDMGEXP, CROPDMG, CROPDMGEXP))

#Damaga by type in dollars
data_noaa_subset <- data_noaa_subset %>%
    mutate(PROPDMG_MOD = case_when(PROPDMGEXP=="K" ~ PROPDMG*1000, PROPDMGEXP=="M" ~ PROPDMG*1000000, PROPDMGEXP=="B" ~ PROPDMG*1000000000, TRUE ~ NA_real_),
           CROPDMG_MOD = case_when(CROPDMGEXP=="K" ~ CROPDMG*1000, CROPDMGEXP=="M" ~ CROPDMG*1000000, CROPDMGEXP=="B" ~ CROPDMG*1000000000, TRUE ~ NA_real_))

#Total damage: property damage + crop damage
data_noaa_subset <- data_noaa_subset %>%
    mutate(TOTAL_DMG = rowSums(data_noaa_subset[,8:9], na.rm=TRUE),
           FATAL_INJUR = rowSums(data_noaa_subset[,2:3], na.rm=TRUE))

Results

Effects on the population health

The first question is wich types of events are most harmful with respect to the population health. In this case, we approximate the population health with the number of fatalities and injuries.

First, we calculate the total number of fatalities and injures by event.

health_effects <- data_noaa_subset %>%
    group_by(EVTYPE) %>%
    summarise(TOT_FATALITIES = sum(FATALITIES, na.rm = TRUE),
              TOT_INJURIES = sum(INJURIES, na.rm = TRUE),
              TOT_FATAL_INJUG = sum(FATAL_INJUR, na.rm = TRUE)) %>%
    ungroup()

health_effects <- subset(health_effects, TOT_FATAL_INJUG > 0)

#There are 220 event types with a positive number of fatalities or injuries. For the present análisis, we select the top 10 events.
health_effects <- arrange(health_effects, desc(TOT_FATAL_INJUG))
health_effects <- health_effects[1:10,]

health_effects
## # A tibble: 10 x 4
##    EVTYPE            TOT_FATALITIES TOT_INJURIES TOT_FATAL_INJUG
##    <fct>                      <dbl>        <dbl>           <dbl>
##  1 TORNADO                     5633        91346           96979
##  2 EXCESSIVE HEAT              1903         6525            8428
##  3 TSTM WIND                    504         6957            7461
##  4 FLOOD                        470         6789            7259
##  5 LIGHTNING                    816         5230            6046
##  6 HEAT                         937         2100            3037
##  7 FLASH FLOOD                  978         1777            2755
##  8 ICE STORM                     89         1975            2064
##  9 THUNDERSTORM WIND            133         1488            1621
## 10 WINTER STORM                 206         1321            1527

According to the data, the event with the highest number of fatalities and injures is “tornado”.

ggplot(health_effects, aes(y=TOT_FATALITIES, x=reorder(EVTYPE, TOT_FATALITIES))) + 
    geom_bar(position="dodge", stat="identity") + 
    coord_flip() + 
    xlab("Event  Type") + 
    ylab("Total Injuries and Fatalities") + 
    ggtitle("Top most harmful eventes - Heatlh effects")

The second question is wich types of events are most harmful with respect to the economic consequences. In this case, we approximate the economic consecuenses with the estimated damages in dollars. We consider the total of property damages and crop damages.

economic_effects <- data_noaa_subset %>%
    group_by(EVTYPE) %>%
    summarise(TOTAL_PROP_DAMAGE = sum(PROPDMG_MOD, na.rm = TRUE),
              TOTAL_CROP_DAMAGE = sum(CROPDMG_MOD, na.rm = TRUE),
              TOTAL_ECONOMIC_DAMAGE = sum(TOTAL_DMG, na.rm = TRUE)) %>%
    ungroup()

economic_effects <- subset(economic_effects, TOTAL_ECONOMIC_DAMAGE > 0)

#There are 426 event types with a positive number damages. For the present análisis, we select the top 10 events.
economic_effects <- arrange(economic_effects, desc(TOTAL_ECONOMIC_DAMAGE))
economic_effects <- economic_effects[1:10,]

economic_effects
## # A tibble: 10 x 4
##    EVTYPE            TOTAL_PROP_DAMAGE TOTAL_CROP_DAMAGE TOTAL_ECONOMIC_DAMAGE
##    <fct>                         <dbl>             <dbl>                 <dbl>
##  1 FLOOD                  144657709800        5661968450          150319678250
##  2 HURRICANE/TYPHOON       69305840000        2607872800           71913712800
##  3 TORNADO                 56925660480         414953110           57340613590
##  4 STORM SURGE             43323536000              5000           43323541000
##  5 HAIL                    15727366720        3025537450           18752904170
##  6 FLASH FLOOD             16140811510        1421317100           17562128610
##  7 DROUGHT                  1046106000       13972566000           15018672000
##  8 HURRICANE               11868319010        2741910000           14610229010
##  9 RIVER FLOOD              5118945500        5029459000           10148404500
## 10 ICE STORM                3944927810        5022113500            8967041310

The most harmful event y terms of economic damages are floods, followed by hurracane/typhoon. We observe differences in property damages and crop damages by event, with could be analyse in the future.

options(scipen=10000)

ggplot(economic_effects, aes(y=TOTAL_ECONOMIC_DAMAGE, x=reorder(EVTYPE, TOTAL_ECONOMIC_DAMAGE))) + 
    geom_bar(position="dodge", stat="identity") + 
    coord_flip() + 
    xlab("Event  Type") + 
    ylab("Total economic damages (US Dollars)") + 
    ggtitle("Top most harmful eventes - Economic effects")