Visualizing Flood Data
This dataset was provided by a number of different sources, including the National Oceanic and Atmospheric Administration and FEMA and it gives good insight into floods from 2006-2021. The dataset provided everything from descriptions of the floods to injuries/deaths and dates of the floods. For this analysis, the data and location of the flood are considered, though further analysis may go deeper.
In the above figure, the number of floods over a period of time (2006-2021) is seen. From this visualization, it is pretty clear that floods tend to be localized to certain states, including California and many of the states in the midwest. This makes sense as the midwest tends to get bad weather that floods the Mississippi river. Additionally, the southeast states tend to get hit hard but more sporadic. The likely cause is the strength of the hurricane seasons.
When looking at floods, it is helpful to observe the data over a period of a year to make some initial observations on the seasonality of the data. Below is a figure showing the month-by-month flood data for 2016, which was a bad year for flooding.
As seen in the figure above, there does not appear to be definite seasonality, though localized seasonality on a per-state basis could exist. It is easy to see which states get affected by different types of floods, whether they are due to hurricanes or rivers overflowing.
It is also very helpful to look at small multiples of plots over a period of time. Below is three figures of flood data, each from a different year, each showing how different states were affected by floods. Note the states with high bars in some years and low bars in other years. This is a pretty clear indication of a lack of seasonality, but perhaps some cycles exist.
The figure above clearly shows significant differences in flood years vs non-flood years. In certain years, like 2016, states like Mississippi get hit far harder than other states, but in some years, like 2012, there are barely any floods across the board. Also, when looking at each of the states across the years, certain states have a flood season while certain states have floods periodically, but no trend seems to be present.
A couple of interesting states to look at when it comes to flooding are states in the Midwest like Indiana and states in the south that get hurricanes like Texas and California, as it usually has a flood season. The graphics below show each of the states' time series plots for floods.
In Indiana, floods don't seem to hit that hard except for certain years. In 2016, Indiana had triple the number of floods it usually had, which seems like an outlier. There seems to be a seasonal trend in California, but there are relatively predictable bad flood years that are exponentially worse. This can be seen in the spikes in the data. Texas had an interesting flood plot as there is one definitive spike in 2016 followed by very few floods comparatively.