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 .
How do we classify droughts?
Short-term droughts are typically defined when conditions last less than six months , while long-term droughts are defined as lasting over half a year.
How are drought measured and classified?
The Palmer Z-Index measures short-term drought on a monthly scale . The Palmer Crop Moisture Index (CMI) measures short-term drought on a weekly scale and is used to quantify drought’s impacts on agriculture during the growing season. ... The hydrological impacts of drought (e.g., reservoir levels, groundwater levels, etc.)
How do drought experts measure drought?
Hydrologists use stream gauges that they place at different points in rivers and streams to find out how much water is flowing in a river or stream from place to place. During droughts, less water flows , and the water that is in the river or stream will be moving much more slowly than normal.
Is there a rating scale for droughts?
Credit: NOAA’s National Weather Service. ... The USDM’s drought intensity scale is composed of five different levels: D0, D1, D2, D3, and D4 . The abnormally dry category, D0, corresponds to an area experiencing short-term dryness that is typical with the onset of drought.
What are 4 types of drought?
As a result, the climatological community has defined four types of drought: 1) meteorological drought, 2) hydrological drought, 3) agricultural drought, and 4) socioeconomic drought.
What are 5 causes of drought?
- 1) Land and water temperatures cause drought. ...
- 2) Air circulation and weather patterns also cause drought. ...
- 3) Soil moisture levels also contribute to drought. ...
- 4) Drought can also be a supply and demand of water issue.
What are 2 interesting facts about droughts?
01Drought can last as long as a week, a month, a year, or even more. 02 Lack of precipitation in an area is one of the major causes of drought. 03Due to the lack of water for crop irrigation, drought can also affect the food chain – resulting in famine. 04As the climate warms, droughts become more common.
How hard is it to predict a drought?
Sometimes. Many droughts can be predicted up to a month in advance, 1 , 2 and in rare cases it may be possible to predict drought conditions more than a year in advance. However, the complexity of Earth’s climate makes drought forecasting very difficult .
What 3 things determine how bad a drought is?
The most common index used to define and monitor drought is the Palmer Drought Severity Index (PDSI), which attempts to measure the duration and intensity of long-term, spatially extensive drought, based on precipitation, temperature, and available water content data .
What is Level 3 drought?
That means conditions are severely dry and adverse impacts to socio-economic or ecosystem values are possible . Conservation and local water restrictions are likely.
What is the difference between extreme and exceptional droughts?
Crop or pasture loss likely, fire risk very high, water shortages common , water restrictions imposed. Extreme Drought (D3): Major crop/pasture losses, extreme fire danger, widespread water shortages or restrictions. Exceptional Drought (D4):
Is BC in a drought?
The Lower Mainland, Vancouver Island, and the Lower Columbia water basins are now at drought Level 4 as of last week. “British Columbia ranks drought levels from 0 to 5. Drought Level 5 is the most severe, with adverse impacts to socioeconomic or ecosystem values almost certain,” said the province in a press release.
What is the longest drought in history?
The three longest drought episodes occurred between July 1928 and May 1942 (the 1930s Dust Bowl drought ), July 1949 and September 1957 (the 1950s drought), and June 1998 and December 2014 (the early 21st-century drought).
What are the main causes of drought?
Droughts are caused by low precipitation over an extended period of time . Atmospheric conditions such as climate change, ocean temperatures, changes in the jet stream, and changes in the local landscape are all factors that contribute to drought.
How many types of drought are there?
It is a creeping phenomenon that slowly sneaks up and impacts many sectors of the economy, and operates on many different time scales. As a result, the climatological community has defined four types of drought: 1) meteorological drought, 2) hydrological drought, 3) agricultural drought, and 4) socioeconomic drought.
