What factors make up the U.S. Drought Monitor?
AUSTIN (KXAN) -- The United States Drought Monitor is a map released every Thursday morning showing the different levels of drought in the area.
The lowest level of the six tells us that conditions are normal. The next level down is considered abnormally dry, areas that may be going into or are coming out of drought.
From there we go to the next four levels of drought beginning with moderate, then severe, followed by extreme and capped by exceptional.
A MODERATE drought can trigger voluntary water restrictions and increase wildfire frequency. In a SEVERE drought, soil is hard making it difficult to plant. Local burn bans are implemented.
Some of what happens in an EXTREME drought include decreased yields for irrigated crops, the soil has large cracks and reservoir levels drop significantly.
The worst is the EXCEPTIONAL drought. Here, water quality is low. Widespread crop loss can occur, and water levels can be near historic lows.
The U.S. Drought Monitor has been around since 1999. It's produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the National Oceanic and Atmospheric Administration and the United States Department of Agriculture. These three agencies will rotate in two-week increments who will author the newest Drought Monitor. Their job is to make sense of data that is going in different directions, something that a computer can't decipher.
Our discussion during weathercasts on the drought monitor will always include rain, or lack thereof, that will go into constructing the newest release.
The agency responsible for that week's release does take precipitation as the major player but there are other data sources that go hand in hand including streamflow, reservoir levels, evaporation, soil moisture and vegetation health. It isn't just one piece of data that is used to tell the story.
There is one other factor that comes into play here. The experts also must understand what is normal for a given location and a given season in addition to short-term and long-term weather patterns. And, of course, there is La Niña and El Niño.
The drought monitor is not a statistical model. It's a blend of the six factors listed above that play a major role in drought impacts. There are as many as 450 contributors who submit their data allowing for expert interpretation.
As previously mentioned, the U.S. Drought Monitor is released every Thursday at 7:30 a.m. incorporating data received up to 7 a.m. the previous Tuesday. So, as an example, significant rain that fell in the afternoon on a Tuesday would NOT be factored in the newest release of the drought monitor.
This looking back in time is a snapshot of the most current conditions. Data collected on Tuesday builds upon the previous week's map.
Who uses this important product? Just about everyone in one way or the other. For example, the United States Department of Agriculture uses it to help trigger disaster declarations. The Internal Revenue Service uses the drought monitor for tax deferral on forced livestock sales due to drought. In short, it is used nationally, and on state, local and tribal levels.
Drought is a part of our climate. It can do a lot of damage because it's considered a slow-moving hazard. Losses from drought are as costly as those from hurricanes and tornadoes. All of these disasters can affect water supply, energy production, public health and wildlife.
The importance of the U.S. Drought Monitor should not be underestimated. The tool is important for just about all facets of life.