library(dplyr)
library(ggplot2)

storm <- read.csv("repdata_data_StormData.csv.bz2", stringsAsFactors = FALSE)

dim(storm)
## [1] 902297     37
head(storm)
##   STATE__           BGN_DATE BGN_TIME TIME_ZONE COUNTY COUNTYNAME STATE  EVTYPE
## 1       1  4/18/1950 0:00:00     0130       CST     97     MOBILE    AL TORNADO
## 2       1  4/18/1950 0:00:00     0145       CST      3    BALDWIN    AL TORNADO
## 3       1  2/20/1951 0:00:00     1600       CST     57    FAYETTE    AL TORNADO
## 4       1   6/8/1951 0:00:00     0900       CST     89    MADISON    AL TORNADO
## 5       1 11/15/1951 0:00:00     1500       CST     43    CULLMAN    AL TORNADO
## 6       1 11/15/1951 0:00:00     2000       CST     77 LAUDERDALE    AL TORNADO
##   BGN_RANGE BGN_AZI BGN_LOCATI END_DATE END_TIME COUNTY_END COUNTYENDN
## 1         0                                               0         NA
## 2         0                                               0         NA
## 3         0                                               0         NA
## 4         0                                               0         NA
## 5         0                                               0         NA
## 6         0                                               0         NA
##   END_RANGE END_AZI END_LOCATI LENGTH WIDTH F MAG FATALITIES INJURIES PROPDMG
## 1         0                      14.0   100 3   0          0       15    25.0
## 2         0                       2.0   150 2   0          0        0     2.5
## 3         0                       0.1   123 2   0          0        2    25.0
## 4         0                       0.0   100 2   0          0        2     2.5
## 5         0                       0.0   150 2   0          0        2     2.5
## 6         0                       1.5   177 2   0          0        6     2.5
##   PROPDMGEXP CROPDMG CROPDMGEXP WFO STATEOFFIC ZONENAMES LATITUDE LONGITUDE
## 1          K       0                                         3040      8812
## 2          K       0                                         3042      8755
## 3          K       0                                         3340      8742
## 4          K       0                                         3458      8626
## 5          K       0                                         3412      8642
## 6          K       0                                         3450      8748
##   LATITUDE_E LONGITUDE_ REMARKS REFNUM
## 1       3051       8806              1
## 2          0          0              2
## 3          0          0              3
## 4          0          0              4
## 5          0          0              5
## 6          0          0              6

Synopsis

This analysis examines the NOAA Storm Database to identify the weather event types that caused the greatest harm to population health and the greatest economic damage in the United States. Population health impact was measured using total fatalities and injuries. Economic impact was measured using total property and crop damage.

Data Processing

The NOAA Storm Database was loaded into R from the compressed CSV file. Event types were grouped using the EVTYPE variable. For population health, fatalities and injuries were summed for each event type. For economic damage, property and crop damage values were converted according to their exponent codes: K for thousands, M for millions, and B for billions.

Population Health Impact

health <- storm %>% group_by(EVTYPE) %>%
summarise(fatalities = sum(FATALITIES, na.rm = TRUE), injuries = sum(INJURIES, na.rm = TRUE)) %>% mutate(total_health = fatalities + injuries) %>% arrange(desc(total_health))

head(health, 10)
## # A tibble: 10 × 4
##    EVTYPE            fatalities injuries total_health
##    <chr>                  <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

Poplulation Health Impact

top_health <- head(health, 10)

ggplot(top_health,aes(x = reorder(EVTYPE, total_health),y = total_health)) + geom_col(fill = "steelblue") + coord_flip() + labs(title = "Top 10 Weather Events Harmful to Population Health", x = "Event Type", y = "Total Fatalities and Injuries")

## Economic Impact

storm$PROPDMGEXP <- toupper(storm$PROPDMGEXP)
storm$CROPDMGEXP <- toupper(storm$CROPDMGEXP)

storm$PROPDMGVALUE <- ifelse(storm$PROPDMGEXP == "K",
                             storm$PROPDMG * 1000,
                      ifelse(storm$PROPDMGEXP == "M",
                             storm$PROPDMG * 1e6,
                      ifelse(storm$PROPDMGEXP == "B",
                             storm$PROPDMG * 1e9,
                             storm$PROPDMG)))

storm$CROPDMGVALUE <- ifelse(storm$CROPDMGEXP == "K",
                             storm$CROPDMG * 1000,
                      ifelse(storm$CROPDMGEXP == "M",
                             storm$CROPDMG * 1e6,
                      ifelse(storm$CROPDMGEXP == "B",
                             storm$CROPDMG * 1e9,
                             storm$CROPDMG)))

economic <- storm %>%
  group_by(EVTYPE) %>%
  summarise(
    total_damage = sum(PROPDMGVALUE + CROPDMGVALUE,
                       na.rm = TRUE)
  ) %>%
  arrange(desc(total_damage))

head(economic, 10)
## # A tibble: 10 × 2
##    EVTYPE             total_damage
##    <chr>                     <dbl>
##  1 FLOOD             150319678257 
##  2 HURRICANE/TYPHOON  71913712800 
##  3 TORNADO            57352114049.
##  4 STORM SURGE        43323541000 
##  5 HAIL               18758221521.
##  6 FLASH FLOOD        17562129167.
##  7 DROUGHT            15018672000 
##  8 HURRICANE          14610229010 
##  9 RIVER FLOOD        10148404500 
## 10 ICE STORM           8967041360
top_economic <- head(economic, 10)

ggplot(
  top_economic,
  aes(
    x = reorder(EVTYPE, total_damage),
    y = total_damage / 1e9
  )
) +
  geom_col(fill = "darkred") +
  coord_flip() +
  labs(
    title = "Top 10 Weather Events by Economic Damage",
    x = "Event Type",
    y = "Total Economic Damage (Billions of Dollars)"
  )

Results

The analysis showed that tornadoes caused the greatest impact on population health, resulting in the highest combined number of fatalities and injuries. Floods caused the greatest economic damage when property and crop losses were combined. These findings suggest that different weather events have different types of impacts, with tornadoes posing the greatest risk to human health and floods causing the largest financial losses.