What Is a Drought?

It's been a while since you've seen a chance of rain in your forecast... could your city be in danger of a drought? 

You'll be glad to know that although a lack of rain or snow over a period of several days, or even a week, is unusual, it doesn't necessarily mean you're headed for a drought.

Droughts are periods (typically several weeks or longer) of abnormally dry and precipitation-less weather. How dry depends on the amount of precipitation that's normal for a location's climate.

A common misconception of droughts is that they're brought on by periods of no rain or snow. While this certainly can initiate drought conditions, oftentimes the onset of a drought is less noticeable. If you're seeing rain or snow, but are seeing it in lighter amounts -- a drizzle here and flurries there, rather than steady rain or snow showers -- this can also signal a drought in-the-making. Of course, you won't be able to determine this as a cause for weeks, months, or even years into the future. That's because, unlike other forms of severe weather and natural disasters, droughts develop slowly from a build-up of small changes in precipitation patterns, rather than from one single event.

Atmospheric conditions such as climate change, ocean temperatures, changes in the jet stream, and changes in the local landscape are all culprits in the long story of the causes of droughts.

How Droughts Hurt

Droughts are some of the most costly economic stressors. Frequently, droughts are billion dollar weather events and are one of the top three threats to population in the world (along with famine and flooding). There are three main ways droughts impact lives and communities:

1. Farmers are often the first to feel the stresses from drought, and feel them hardest. The economic impacts of drought include losses in the timber, agricultural, and fisheries communities. Many of these losses are then passed on to consumers in the form of higher food prices. In less developed countries, once crops fail, famine can become a major problem. 
2. Social impacts include increased chance of conflict over commodities, fertile land, and water resources. Other social impacts include abandonment of cultural traditions, loss of homelands, changes in lifestyle, and increased chance of health risks due to poverty and hygiene issues.
3. The environmental impacts of drought include loss in species biodiversity, migration changes, reduced air quality, and increased soil erosion.

Types of Droughts

While droughts can be defined in many ways, three main drought types are commonly discussed:

• Hydrological Drought. Many watersheds experience depleted amounts of available water. Lack of water in river systems and reservoirs can impact hydroelectric power companies, farmers, wildlife, and communities.
• Meteorological Drought. A lack of precipitation is the most common definition of drought and is usually the type of drought referred to in news reports and the media. Most locations around the world have their own meteorological definition of drought based on the climate normals in the area. A normally rainy area that gets less rain than usual can be considered in a drought.
• Agricultural Drought. When soil moisture becomes a problem, the agricultural industry is in trouble with drought. Shortages in precipitation, changes in evapo-transpiration, and reduced ground water levels can create stress and problems for crops.​

US Droughts

While droughts don't often cause deaths in the United States, the Dust Bowl in the U.S. Midwest is one example of the devastation that can occur. 

Other parts of the world experience long periods without rains as well. Even during monsoon season, areas (such as Africa and India) that depend on seasonal rains will often experience drought if the monsoon rains fail. 

Preventing, Predicting, and Preparing for Droughts

Want to know how drought is affecting your neighborhood right now? Be sure to monitor these drought resources & links:

• The US Drought Portal - See how drought impacts your community.
• The National Drought Mitigation Center - Great details on the difficulties and successes of predicting droughts are available at the NDMC.
• US Seasonal Drought Outlooks - The National Weather Service provides predictions of the chances of drought across the United States.

Updated by Tiffany Means