Severe Drought in the United States

A short report, rendered to both HTML and PDF

This report accompanies Why HTML?. One source file produces both outputs. Each exhibit has two versions: a static figure for PDF, and an interactive figure for HTML.

Where the data comes from

The U.S. Drought Monitor dataset comes from the National Drought Mitigation Center, the U.S. Department of Agriculture, and the National Oceanic and Atmospheric Administration via TidyTuesday.¹

The dataset contains 325,728 rows across 1044 weeks from July 2001 to July 2021 across 52 states and territories.

Drought severity ranges from D0 (dry) to D4 (exceptional drought). The area_pct column records state area share per level. The primary metric is D2+, the sum of levels D2, D3, and D4.

Note

The Monitor covers the 50 states, the District of Columbia, and Puerto Rico.

The national picture

State land area weights produce national drought shares (Figure 1). The record shows key drought episodes: the West in the early 2000s, a decline in 2010, the 2012 drought, and an increase in 2020.

Hover the line for exact values. Drag the slider or select time buttons to zoom into episodes.

Figure 1: Share of US land area in severe drought (D2+), by week.

The worst week on record

The peak week occurred on August 7, 2012, with 38.5% of national land area affected. Figure 2 displays state drought levels during this period.

Select Play to run the map by quarter. Drag the slider to select a quarter. Hover a state for values.

Figure 2: Share of state area in severe drought (D2+), quarterly average, 2001 to 2021.

The HTML map displays Alaska and Hawaii. The static PDF map boundary file covers the lower 48 states and DC.

The states that stay dry

Persisting drought centers in western states (Table 1). Nevada and Arizona spent over one third of the record in D2 to D4 drought.

Select column headers to sort. Type in the search box to find a state.

Table 1: Average and peak share of area in severe drought, all 52 states and territories, 2001 to 2021.

Footnotes

1. National Drought Mitigation Center, U.S. Department of Agriculture and National Oceanic and Atmospheric Administration, U.S. Drought Monitor. TidyTuesday dataset, week of 2021-07-20: https://github.com/rfordatascience/tidytuesday/tree/main/data/2021/2021-07-20.