Fast Facts
The U.S. Drought Monitor is made with more than precipitation data.
When you think about drought, you probably think about water, or the lack of it. Precipitation plays a
major role in the creation of the drought monitor, but the map’s author considers numerous indicators,
including drought impacts and local insight from over 450 expert observers around the country.
Authors use several dozen indicators to assess drought, including precipitation, streamflow, reservoir
levels, temperature and evaporative demand, soil moisture and vegetation health. Because the
drought monitor depicts both short and long-term drought conditions, the authors must look at data
for multiple timeframes. The final map produced each week represents a summary of the story being
told by all the pieces of data. To help tell that story, authors don’t just look at data - they converse over
the course of the map-making week with experts located across the country and draw information
about drought impacts from media reports and private citizens.
A real person, using real data, makes the USDM.
Each week’s map analyzes new data for the weekly update. The map authors are climatologists or meteorologists
from the National Drought Mitigation Center at the University of Nebraska-Lincoln (the academic partner and web
host of the USDM), the National Oceanic and Atmospheric Administration, and the U.S. Department of Agriculture
(USDA). The author’s job is to do something that a computer can’t. When the data is pointing in different directions,
they make sense out of it.
The USDM is a current snapshot, not a forecast.
The USDM is a “snapshot” of current drought conditions. Each map is an update of the one before. The map
comes out on Thursday, and shows what happened up through Tuesday morning. Precipitation that falls on
Wednesday won’t change the next day’s map, but it might change the next week’s map. This gives the author
at least two days to look at all the data and make a final map.
Drought declarations may or may not be based on the USDM.
Many agencies and organizations look at the USDM, but drought declarations only come from federal, state and
local agencies. Some of them look at the USDM to declare drought, but some look at other indicators as well. USDA
uses the USDM to determine a producer’s eligibility for certain drought assistance programs, like the Livestock
Forage Disaster Program (LFP) and Emergency Haying or Grazing on CRP acres and to “fast-track” Secretarial
drought disaster designations.
The public can be part of the drought-monitoring process.
The USDM triggers federal disaster relief for agricultural producers. Sometimes farmers and ranchers
call, email or better yet use the online reporting system to say drought in their area is worse than what
the latest map shows. When the author gets a report like that, they work with the local experts to look
closely at all available data for that area, to see whether measurements such as rain and temperature
agree with what farmers and ranchers are saying. This is the process that authors follow whether they
get one report or one hundred reports. Reports from more places during drought may help state officials
and others know where to look for impacts.