Water is one of the essential elements for life. It's no wonder that droughts have been described as "creeping natural disasters" that can cause so much distraction and havoc. In fact, the United Nations Food and Agricultural Organization (FAO) reports that droughts have affected more people globally in the last four decades than any other type of natural hazard.
Here's what we know about what causes droughts, and how you can reduce their effects on your home and family.
What Are Droughts?
Droughts are prolonged periods of abnormally low rainfall, leading to a shortage of water. However, as Drought.gov notes, defining the word drought can be exceptionally tricky. It's not always easy to determine when an area is experiencing a drought because it depends on an area's specific weather patterns and climate. The island of Bali may define drought as "a period of six days without rain" – a situation that would be perfectly normal in, say, the Sonoran Desert in Arizona.
5 Types of Droughts
The second part of the definition — leading to a shortage of water — is also not as simple to define because a shortage may also look different depending on the necessity of water in the affected area. These differences in climate and regional water needs has led meteorologists, hydrologists, geologists, climatologists, and other land management professionals to categorize drought into five primary types:
- Meteorological drought is when a region's precipitation is less than expected based on regional climatology data that goes back 30 years, with often historical records over 100 years.
- Agricultural drought happens when the supply of water is not sufficient to meet the needs of crops and livestock in the area.
- Hydrological drought is when the lack of rainfall lasts long enough to reduce the surface and groundwater supplies.
- Socioeconomic drought is determined when the supply and demand of various commodities is affected by drought.
- Ecological drought is determined when natural ecosystems are affected by drought.
Where Do Droughts Happen in the U.S.?
While droughts can happen anywhere, some parts of the U.S. are more prone to suffer from drought conditions than others. Droughts are most common across the West Coast and Southwest and many areas of the Midwest. Nevada and Arizona, two of the country's driest states, are affected by drought most often. The Great Lakes states and the Northeast are the least likely to experience persistent droughts.
What Causes Droughts?
Identifying what causes a drought is just as complex as trying to define it. However, we can outline a combination of both natural and human factors.
Changes in Ocean and Land Temperature
Ocean temperatures have a major effect on precipitation patterns. Researchers have found a correlation between ocean surface temperature changes and droughts in North America and around the Mediterranean.
Altered Weather Patterns
Air movements are one of the factors that contribute to when and where rain falls. When air and land temperatures cause a shift in ocean currents, it can result in unusually wet weather in one place and dry conditions in another.
Reduced Soil Moisture
Soil moisture contributes to the formation of rain clouds. When the soil is unusually dry, it can't return enough moisture into the air, interrupting the water cycle. Many factors contribute to the ability of the soil to retain moisture, including reduced soil quality as a result of deforestation, intensive farming, and other harmful land use practices.
Excess Water Demand
Increases in population, changes in irrigation practices, and other such factors can create a situation where the demand for water is greater than the supply. Scientists have estimated that human water consumption alone led to a 26% increase in droughts worldwide.
While droughts are a natural part of the global weather cycle, it's clear that human actions contribute to and exacerbate their occurrence, leading to more frequent and more extreme weather events of all kinds.
What Are the Impacts of Drought?
Some of the effects of drought are obvious — crop failures, for example. While other effects might not come to mind as quickly when you think about the consequences of a drought, they're important to know and consider when preparing for and living through a period of drought. Some of these less evident impacts include:
- Economic losses resulting from crop failure and livestock loss can reach further than agricultural communities and affect companies that process, package, or transport food.
- Crop failures may result in food shortages, rising food prices, and increasing food insecurity.
- Drier conditions can increase the risk of outdoor activities and recreation, in addition to an increased risk of fire.
- Low water levels in reservoirs and public cisterns can affect drinking water quality.
- Particulate matter — dust, allergens, and other irritants — remain airborne longer in dry air, reducing air quality and exacerbating some chronic conditions.
- Extended periods of drought can make outdoor activities and recreation riskier.
- Heat and dry air can heighten the risk of health issues like hyperthermia.
How To Protect Your Home and Family from Droughts
If your area is in a drought, your local officials will likely announce policies to help conserve water and reduce some of the other hazards associated with drought. They may include restrictions on watering your garden and lawn, prohibiting outdoor fires, and restricting outdoor activities. In addition to abiding by those restrictions, there are some actions you can take to protect your home, garden, and family in the case of drought.
Home and Health:
- Know your area's drought risk. Drought Monitor publishes weekly drought risk assessments for the entire U.S.
- Monitor indoor air quality (IAQ) and take steps to improve your IAQ.
- Use humidifiers to add moisture to the air.
- Keep everyone hydrated, especially young children and older adults.
- Make sure that your pets have easy access to plenty of clean water. They get dehydrated, too.
- If you haven't already, consider installing water-efficient appliances and plumbing to help conserve water.
- Reduce home water consumption, if possible. Easy ways to do this include talking to your family members about taking shorter showers, installing a shower timer, and reducing daily flushes. The old saying goes: If it's yellow, let it mellow. If it's brown, flush it down!
- Use water-efficient irrigation methods, such as drip irrigation or self-watering planters, instead of sprinklers or hoses.
- Water garden plants early in the morning or late in the afternoon to reduce the amount of water lost to evaporation.
- Monitor soil moisture, rainfall, and other factors affecting your garden with an AcuRite Atlas® weather station. Keeping an eye on hyperlocal conditions over time can help you monitor drought development to manage your home and garden water needs more efficiently.
- Follow any local guidelines concerning the use of campfires, barbecues, and other outdoor fires.
- If you do have an outdoor fire, monitor it carefully and ensure that it is completely extinguished when you're done.
- Stay aware of any water quality issues if you're going to be on or near the water. Low water levels encourage the growth of harmful bacteria and plants in recreational waters.
- Watch for flash floods. This may seem counterintuitive in the middle of a drought, but a sudden rainstorm in very dry conditions can cause dangerous flooding; when the ground is too dry, it doesn’t absorb the rain fast enough, so the water runs off and floods surrounding areas.
Want to add to the scientific knowledge about droughts and their causes? Check out the About Us page at the U.S. Drought Monitor for suggestions on how you can be part of the conversation and instructions on submitting your own data and observations. Contribute in the comments section below as well by sharing your stories and ideas about your experiences with managing droughts.