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U.S. Drought Monitor Categories.
| Value | Map Hex Color |
|---|---|
| D2 | #ff6600 |
| D3 | #ff0000 |
| D4 | #660000 |
What is classified as a drought?
Drought is defined as a moisture deficit bad enough to have social, environmental or economic effects. D0 areas are not in drought, but are experiencing abnormally dry conditions that could turn into drought or are recovering from drought but are not yet back to normal.
What instrument measures drought?
The Palmer Z-Index measures short-term drought on a monthly scale. The Palmer Crop Moisture Stress Index (CMSI) measures short-term drought on a weekly scale and is used to quantify drought's impacts on agriculture during the growing season.
How often is the Drought Monitor calculated?
weeklyStatistics are calculated weekly for the U.S. Drought Monitor by two different methods that we refer to as “cumulative,” which is how we did it from the beginning, or “categorical,” meaning we report on one category at a time. Below is an explanation of each method.
Is there a drought in us?
According to the USDM, on March 8, 2022, more than 20 percent of land in Western States was classified as experiencing extreme or exceptional drought. Data reported by the USDM demonstrate that the incidence of drought in the Western U.S. during the summer of 2021 exceeded all past droughts in the region since 2000.
Why is the drought monitor important?
Lower crop yields and reduced access to water leaves livestock vulnerable and at risk. Drought can be easily monitored because its slow onset allows time to observe changes in precipitation, temperature and the status of surface water and groundwater supplies in a region.
How does the Drought Monitor Work?
The U.S. Drought Monitor is a map released every Thursday, showing parts of the U.S. that are in drought. The map uses five classifications: abnormally dry (D0), showing areas that may be going into or are coming out of drought, and four levels of drought: moderate (D1), severe (D2), extreme (D3) and exceptional (D4).
What are the 4 types of drought?
Wilhite and Glantz1 categorized the definitions in terms of four basic approaches to measuring drought: meteorological, hydrological, agricultural, and socioeconomic.
How is drought measured?
Drought indices take thousands of bits of data on rainfall, snowpack, streamflow, etc., analyze the data over various time frames, and turn the data into a comprehensible big picture. A drought index value is typically a single number, which is interpreted on a scale of abnormally wet, average, and abnormally dry.
Is 2022 a drought year?
According to the July 12, 2022, U.S. Drought Monitor The worst drought categories (extreme to exceptional drought) decreased from 14.7% last week to 14.4%, moderate to exceptional drought covers 45.0% of the United States including Puerto Rico, an increase from last week's 44.3%.
How do droughts end?
The only way a drought can really end is with enough regular soaking rains or significant snow. Rains that soak into the soil can replenish the groundwater. Groundwater provides water to plants and can refill streams during non-rainy periods. One soaking rain may help improve drought conditions.
Is 2022 going to be a drought?
According to the July 19, 2022, U.S. Drought Monitor moderate to exceptional drought covers 44.6% of the United States including Puerto Rico, moderate to exceptional drought covers 44.6% of the United States including Puerto Rico, a decrease from last week's 45.0%.
How is drought index calculated?
A drought indicator is calculated using data such as precipitation or soil moisture to provide a measure of the moisture conditions at a location. Drought indicators are calculated with respect to normal moisture conditions.
How is Palmer Drought Severity Index calculated?
The PDSI is calculated based on precipitation and temperature data, as well as the local Available Water Content (AWC) of the soil. From the inputs, all the basic terms of the water balance equation can be determined, including evapotranspiration, soil recharge, runoff, and moisture loss from the surface layer.
How often do droughts occur?
For example, a D1, or Moderate Drought, is expected to occur approximately 2 or 3 times out of every 10 years, and a D4, or Exceptional Drought, is expected to occur 1 or 2 times out of every 100 years (think of the commonly referred to 1-in-100 year event).
How long before a drought is declared?
If a weather pattern that results in a precipitation deficit lasts for a few weeks or months, it is considered short-term drought. If the pattern and precipitation deficits last for more than six months, it is typically considered long-term drought.