Five droughts that changed history by USGS Vizlab

The U.S. has a long history of droughts that have impacted humans and ecosystems. But in the last 100 years, five periods of drought stand out in their effects on agriculture, wildfires, and streamflow (McCabe et al., 2022).
This data visualization website features a “strip-swarm” visual timeline that shows the onset and duration of droughts at USGS streamgages (USGS Streamgage Network) during these major drought periods. The “strip-swarm” chart is a unique variant of a beeswarm chart, with a temporal vertical axis and a single vertical strip for each drought event at a USGS streamgage. Each strip reflects the onset and duration of individual drought events—the taller and darker the bar, the longer the drought event. The compilation of these strips into a swarm layout, where strips for co-occurring droughts are placed adjacent to one another, provides a striking visual of major drought events as the rapid expansion and persistence of drought conditions across many sites.
The timeline chart is enriched by an inset map showing the location of streamgages experiencing drought and by written context about each major drought period, including quotes from those impacted by the droughts. In addition to the main exploratory timeline, the website also includes an interactive radial violin chart that allows the user to compare the timeline of drought across seven regions within the conterminous United States. Data are available from https://doi.org/10.5066/P92FAASD and the code behind the visualizations is available from https://github.com/DOI-USGS/drought-timeline.