From Palmer to the Present: Pushing Drought Monitoring into the 21st Century

As the United States struggled through several major droughts during the last one-quarter of the 20^th century, soil and atmospheric scientists became aware that drought-monitoring techniques were outdated and inadequate. Notably, the Palmer Drought Severity Index (PDSI) and Crop Moisture Index (CMI) showed limitations in assessing the rapidly evolving, large-scale droughts of 1980, 1983, and 1988, which collectively caused more than $100 billion (CPI-adjusted) in economic losses, mainly to agriculture and related industries, according to the National Oceanic and Atmospheric Administration’s (NOAA’s) Billion-Dollar Weather and Climate Disasters. Less than a decade later, National Drought Mitigation Center (NDMC) founding director Don Wilhite assigned climatologist Mark Svoboda to find every drought-related index, indicator, and tool that existed. Svoboda made a presentation on drought mapping at the 1998 American Meteorological Society (AMS) annual meeting in Phoenix, Arizona. At that 1998 meeting, Svoboda and another attendee, Douglas Le Comte of the National Weather Service’s Climate Prediction Center (NWS/CPC), agreed to join forces in helping to combine various drought indices into a single map. Svoboda, currently the NDMC director, later recalled, “That’s where the idea was born to make a high-resolution [drought] map from combining several indicators.” Their collaboration culminated in the creation of the United States Drought Monitor (USDM), which celebrated its 25^th anniversary in 2024. Every week since the USDM was unveiled at a White House press conference on August 11, 1999, the NDMC, the United States Department of Agriculture (USDA), and NOAA have teamed up to release the Drought Monitor. In autumn 1999, six lead authors were placed into the USDM rotation. This group included product founders Mark Svoboda (NDMC) and Douglas Le Comte (NWS/CPC), along with four others: Michael Hayes of NDMC, Brad Rippey of USDA, and David Miskus and Rich Tinker of NWS/CPC. This paper will briefly explore the history of drought monitoring in the United States and carry through to the present day, with a first-hand focus on the early years of the USDM, as well as USDA’s usage of the USDM as a drought-assistance tool.