Analysis: A look into the U.S. National Oceanic and Atmospheric Administration's (NOAA) storm database

Synopsis

This document presents an analysis based on data obtained from the U.S. National Oceanic and Atmospheric Administration's (NOAA) storm database. This data presents 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.

The report is separated in three parts. First, we present the process of getting and cleaning the data, reviewing its characteristics and making the corresponding transformations, if applicably. Next, we proceed to analize the effects of these weather events on two aspects: Population Health and the Economy.

The results show that, regarding the population health, the events that have the highest impact are the tornados. When we speak about the economy, the events related with water, such as floods cause the highest damage, with the maximum cost for damage caused to properties and agricultural resources.

Part 1: Data Processing

First we download the data from the U.S. National Oceanic and Atmospheric Administration's (NOAA) storm database. After reviewing the structure, we make the corresponding transformations to adapt it into a suitable form for our analysis.

#Path to read files
path1 <- "C:/Users/Economics05/Documents/Coursera/RR_CP2"
fileUrl1 <- "https://d396qusza40orc.cloudfront.net/repdata%2Fdata%2FStormData.csv.bz2"
filename <- "StormData.csv.bz2"
download.file(fileUrl1, filename, method = "curl")

#Read the file
stormdata <- read.csv(file.path(path1,filename),header = TRUE)

After reading the file, we proceed to check the data structure and review it for any changes.

dim(stormdata)
## [1] 902297     37
head(stormdata)
##   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
str(stormdata)
## '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 ...

As we can see, we need to transform date variables into a suitable format.

#Transform the dates
stormdata$BGN_DATE <- as.Date(stormdata$BGN_DATE,"%m/%d/%Y")
stormdata$END_DATE <- as.Date(stormdata$END_DATE,"%m/%d/%Y")

Part 2: Events and its effects on population health - Results

In order to show the effects of severe weather events on the population, we analyze which one of them are the most harmful with respect to population heath, across the United States.

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

library(ggplot2)
library(dplyr)
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union

We analyze which are the events that have cause the higher amount of injuries among the population. First, we filter the top 1% of events that have caused the higher amount of injuries, by individual event. Then we filter the data to get the events that belong to this group.

topq <- quantile(stormdata$INJURIES, probs = 0.99)
topq
## 99% 
##   2
storm1 <- tbl_df(stormdata)
top <- storm1 %>% select(EVTYPE,INJURIES,BGN_DATE,STATE) %>% filter(INJURIES>topq) %>% arrange(desc(INJURIES)) 
top20_injuries <- top[1:20, ]
head(top20_injuries)
## # A tibble: 6 x 4
##   EVTYPE    INJURIES BGN_DATE   STATE
##   <fct>        <dbl> <date>     <fct>
## 1 TORNADO       1700 1979-04-10 TX   
## 2 ICE STORM     1568 1994-02-08 OH   
## 3 TORNADO       1228 1953-06-09 MA   
## 4 TORNADO       1150 1974-04-03 OH   
## 5 TORNADO       1150 2011-05-22 MO   
## 6 FLOOD          800 1998-10-17 TX
maxinjuries <- prettyNum(max(top$INJURIES), big.mark = ",")
maxinjuries
## [1] "1,700"
maxinjuriestate <- as.vector(top20_injuries$STATE[1]) 
maxinjuriestate
## [1] "TX"

As we can see the 1% of these events, when filtered, gives you the event with the highest number of injuries among the population and it shows that a tornado had the highest impact, reaching 1,700 injuries and it ocurred in the state of TX.

When we procced to group the events by type, we get a look at which ones have been the most dangerous to the population.

storm1 <- tbl_df(stormdata)
topinjuries <- storm1 %>% select(EVTYPE,INJURIES,BGN_DATE,STATE) %>% group_by(EVTYPE, .drop= FALSE) %>% summarise(numinjuries = sum(INJURIES)) %>% arrange(desc(numinjuries)) 

top5_injuries <- topinjuries[1:5, ]
maxinj <- prettyNum(max(topinjuries$numinjuries), big.mark = ",")
maxinj
## [1] "91,346"
maxinjevent <- as.vector(top5_injuries$EVTYPE[1]) 
maxinjevent
## [1] "TORNADO"
top5_injuries
## # A tibble: 5 x 2
##   EVTYPE         numinjuries
##   <fct>                <dbl>
## 1 TORNADO              91346
## 2 TSTM WIND             6957
## 3 FLOOD                 6789
## 4 EXCESSIVE HEAT        6525
## 5 LIGHTNING             5230
graph2 <- ggplot(data = top5_injuries, aes(EVTYPE, numinjuries)) + geom_bar(stat = "identity", fill = "Dark Green") + labs(x="Type of event", y="Number of injuries") + ggtitle("Weather events with highest number of injuries in the US: Top 5") + theme(axis.text.x = element_text(angle = 90))+ theme_minimal()
graph2

As the graph shows, the highest number of injuries belongs, again, to the TORNADO with 91,346 .

When we talk about population health, we need also to review the number of fatalities caused by these events. For this section, we proceed to review which events have the highest number of attribuited deaths.

storm1 <- tbl_df(stormdata)
topfat <- storm1 %>% select(EVTYPE,FATALITIES,BGN_DATE,STATE) %>% group_by(EVTYPE) %>% summarise(numfatalities = sum(FATALITIES)) %>% arrange(desc(numfatalities)) 
## `summarise()` ungrouping output (override with `.groups` argument)
top20_fatalities <- topfat[1:20, ]
maxfat <- prettyNum(max(topfat$numfatalities), big.mark = ",")
maxfat
## [1] "5,633"
maxfatalitiesevent <- as.vector(top20_fatalities$EVTYPE[1]) 
maxfatalitiesevent
## [1] "TORNADO"
top5fat <- topfat[1:5, ]
top5fat
## # A tibble: 5 x 2
##   EVTYPE         numfatalities
##   <fct>                  <dbl>
## 1 TORNADO                 5633
## 2 EXCESSIVE HEAT          1903
## 3 FLASH FLOOD              978
## 4 HEAT                     937
## 5 LIGHTNING                816
graph3 <- ggplot(data = top20_fatalities, aes(EVTYPE, numfatalities)) + geom_bar(stat = "identity", fill = "Dark Green") + labs(x="Type of event", y="Number of fatalities") + ggtitle("Weather events with highest number of fatalities in the US: Top 20")+ theme(axis.text.x = element_text(angle = 90))
graph3

When we review the top 5 number of fatalities caused by weather events, we can see again the influence of the wind-related events among the population health. The highest number of casualities, 5,633, are caused by the TORNADO. Also, we see events related to hotter climat, with the Excessive Heat and Heat, comming in second and fourth place. Flash Flood, in third and Lightning in fifth.

Part 3: Events and its effects on the economy - Results

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

First, we transform the data of the property and crop damage into comparable magnitudes, using as reference the alfabethical characters "K" for thousands, "M" for millions, and "B" for billions, that has been established by the NOAA data documentation. The cells with no character (NA, ?,-,+) get a factor value of one (10^0), the numeric ones get a factor of 10 (10^1). After this, we can proceed to compare the effects.

storm1$PROPDMGEXP <- toupper(storm1$PROPDMGEXP)
storm1$CROPDMGEXP <- toupper(storm1$CROPDMGEXP)
storm1$PROPDMGEXP <- as.character(storm1$PROPDMGEXP)
storm1$CROPDMGEXP <- as.character(storm1$CROPDMGEXP)
mag1 <- table(storm1$PROPDMGEXP)
mag2 <- table(storm1$CROPDMGEXP)
mag1
## 
##             -      ?      +      0      1      2      3      4      5      6 
## 465934      1      8      5    216     25     13      4      4     28      4 
##      7      8      B      H      K      M 
##      5      1     40      7 424665  11337
mag2
## 
##             ?      0      2      B      K      M 
## 618413      7     19      1      9 281853   1995
#Every value must be converted to USD Dollars with a factor, when we have numbers, we assume of 10^1 for the factor, since the meaning is not specified in the data documentation manual.

storm1$factorprop[(storm1$PROPDMGEXP == "")] <- 10^0
## Warning: Unknown or uninitialised column: `factorprop`.
storm1$factorprop[(storm1$PROPDMGEXP == "-")] <- 10^0
storm1$factorprop[(storm1$PROPDMGEXP == "?")] <- 10^0
storm1$factorprop[(storm1$PROPDMGEXP == "+")] <- 10^0
storm1$factorprop[(storm1$PROPDMGEXP == "0")] <- 10^0
storm1$factorprop[(storm1$PROPDMGEXP == "1")] <- 10^1
storm1$factorprop[(storm1$PROPDMGEXP == "2")] <- 10^1
storm1$factorprop[(storm1$PROPDMGEXP == "3")] <- 10^1
storm1$factorprop[(storm1$PROPDMGEXP == "4")] <- 10^1
storm1$factorprop[(storm1$PROPDMGEXP == "5")] <- 10^1
storm1$factorprop[(storm1$PROPDMGEXP == "6")] <- 10^1
storm1$factorprop[(storm1$PROPDMGEXP == "7")] <- 10^1
storm1$factorprop[(storm1$PROPDMGEXP == "8")] <- 10^1
storm1$factorprop[(storm1$PROPDMGEXP == "B")] <- 10^9
storm1$factorprop[(storm1$PROPDMGEXP == "H")] <- 10^2
storm1$factorprop[(storm1$PROPDMGEXP == "K")] <- 10^3
storm1$factorprop[(storm1$PROPDMGEXP == "M")] <- 10^6

storm1$factorcrop[(storm1$CROPDMGEXP == "")] <- 10^0
## Warning: Unknown or uninitialised column: `factorcrop`.
storm1$factorcrop[(storm1$CROPDMGEXP == "?")] <- 10^0
storm1$factorcrop[(storm1$CROPDMGEXP == "0")] <- 10^0
storm1$factorcrop[(storm1$CROPDMGEXP == "2")] <- 10^0
storm1$factorcrop[(storm1$CROPDMGEXP == "B")] <- 10^9
storm1$factorcrop[(storm1$CROPDMGEXP == "K")] <- 10^3
storm1$factorcrop[(storm1$CROPDMGEXP == "M")] <- 10^6

#Convert Property Damage and Crop Damage in comparable magnitudes
ecdamage <- storm1 %>% select(EVTYPE,INJURIES,FATALITIES,BGN_DATE,STATE, PROPDMG, factorprop, CROPDMG, factorcrop) %>% mutate(Proptotal = PROPDMG * factorprop) %>% mutate(Croptotal = CROPDMG * factorcrop) %>% mutate(Totaldmg = Proptotal + Croptotal)

top2 <- quantile(ecdamage$Totaldmg, probs = 0.99)
top2
##   99% 
## 2e+06
top_economy <- ecdamage %>% filter(Totaldmg>top2) %>% arrange(desc(Totaldmg)) 
top20_economy <- top_economy[1:20, ]

graph4 <- ggplot(data = top20_economy, aes(x= EVTYPE,Totaldmg)) + geom_bar(stat = "identity", fill = "Dark Green") + labs(x="Type of event", y="Total damage expressed in US Dollars") + ggtitle("Weather events with the greatest economic consequenses in the US") + theme(axis.text.x = element_text(angle = 90))
graph4

topcostevent <- as.vector(top20_economy$EVTYPE[1])
topcostevent
## [1] "FLOOD"
topcostusd <- prettyNum(top20_economy$Totaldmg[1], big.mark = ",") 
topcostusd
## [1] "115,032,500,000"

As we can see, the highest cost for the economy is directly related to FLOOD with a total amount of 115,032,500,000 US dollars.

Conclusion

After reviewing the previous data, we can say that weather-related events have a lasting impact on population health and the economy. That is why, is always important to be alert and prepared with all the available information, to prevent major consequences.