A drought is a period of drier-than-normal conditions. A drought can last for days, months or years. Drought often has large impacts on the ecosystems and agriculture of affected regions, and causes harm to the local economy. Annual dry seasons in the tropics significantly increase the chances of a drought developing and subsequent wildfires. Periods of heat can significantly worsen drought conditions by hastening evaporation of water vapour, drying out forests and other vegetation and increasing fuel for wildfires.
The United Kingdom straddles the higher mid-latitudes between 49° and 61°N on the western seaboard of Europe. Since the UK is always in or close to the path of the polar front jet stream, frequent changes in pressure and unsettled weather are typical. Many types of weather can be experienced in a single day.
Aridity is the condition of a region that severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most arid climates are located in the subtropics; these regions include parts of Africa, Asia, South America, North America, and Australia.
Lake Lanier is a reservoir in the northern portion of the U.S. state of Georgia. It was created by the completion of Buford Dam on the Chattahoochee River in 1956, and is also fed by the waters of the Chestatee River. The lake encompasses 38,000 acres (150 km2) or 59 sq mi (150 km2) of water, and 692 mi (1,114 km) of shoreline at normal level, a "full pool" of 1,071 ft (326 m) above mean sea level and the exact shoreline varies by resolution according to the coastline paradox. Named for confederate poet Sidney Lanier, it was built and is operated by the U.S. Army Corps of Engineers for flood control and water supplies. Its construction destroyed more than 50,000 acres (20,000 ha) of farmland and displaced more than 250 families, 15 businesses, and relocated 20 cemeteries along with their remains in the process.
A period of unusually hot summer weather occurred in the British Isles during the summer of 1976. At the same time, there was a severe drought on the islands of Great Britain and Ireland. It was one of the driest, sunniest and warmest summers (June/July/August) in the 20th century, although the summer of 1995 is now regarded as the driest. Only a few places registered more than half their average summer rainfall. In the Central England temperature record, it was the warmest summer in the series until being surpassed in the 21st century. It was the warmest summer in the Aberdeen area since at least 1864, and the driest summer since 1868 in Glasgow.
Drought in Australia is defined by the Australian Bureau of Meteorology as rainfall over period greater than three-months being in the lowest decile of what has been recorded for that region in the past. This definition takes into account that drought is a relative term and rainfall deficiencies need to be compared to typical rainfall patterns including seasonal variations. Specifically, drought in Australia is defined in relation to a rainfall deficiency of pastoral leases and is determined by decile analysis applied to a certain area. Note that this definition uses rainfall only because long-term records are widely available across most of Australia. However, it does not take into account other variables that might be important for establishing surface water balance, such as evaporation and condensation.
Winterburn Reservoir is located near the village of Winterburn in Malhamdale, North Yorkshire, England. It was constructed between 1885 and 1893 by Leeds civil engineers Henry Rofe and Edward Filliter to help maintain levels on the Leeds and Liverpool Canal. The cost of construction was estimated at £45,000. Its capacity is 281,504,000 imperial gallons (1.27974×109 L; 338,072,000 US gal) and covers an area of 39.17 acres (15.85 ha)
Severe weather is any dangerous meteorological phenomenon with the potential to cause damage, serious social disruption, or loss of human life. Types of severe weather phenomena vary, depending on the latitude, altitude, topography, and atmospheric conditions. High winds, hail, excessive precipitation, and wildfires are forms and effects of severe weather, as are thunderstorms, downbursts, tornadoes, waterspouts, tropical cyclones, and extratropical cyclones. Regional and seasonal severe weather phenomena include blizzards (snowstorms), ice storms, and duststorms.
The United States' contiguous western and especially southwestern region has experienced widespread drought since about year 2000. Below normal precipitation leads to drought, and is caused by an above average persistence of high pressure over the affected area. Changes in the track of extratropical cyclones, which can occur during climate cycles such as the El Niño-Southern Oscillation, or ENSO, as well as the North Atlantic Oscillation, Pacific Decadal Oscillation, and Atlantic multidecadal oscillation, modulate which areas are more prone to drought. Increased drought frequency and severity is also expected to be one of the effects of global warming.
Droughts are a relatively common feature of the weather in the United Kingdom, with one around every 5–10 years on average. These droughts are usually during the summer, when a blocking high causes hot, dry weather for an extended period. However this means that droughts can vary in their characteristics. All types of drought cause issues across all sectors, with impacts extending to the ecosystem, agriculture and the economy of the whole country in severe cases of drought. The south east of the country usually suffers most, as it has the highest population and the lowest average precipitation per year, which is even lower in a drought. Even in these areas in severe droughts, the definition, impacts, effects and management are all minimal in comparison to drought prone areas such as Australia and parts of the United States. In recent years however, the summers of 2007, 2008, 2009, August 2010 and 2012 were wetter than normal, 2007 being wettest on record. Droughts have continued to occur in recent times, with spring 2011, July 2013, summer 2018, spring 2020, spring and summer 2022 and May and June 2023 all featuring excessively dry periods for part or all of the UK, and will likely become more severe due to climate change over the 21st century.
During the 1990 heat wave in the United Kingdom a weather station recorded a temperature of 37.1 °C (98.8 °F) for Cheltenham, Gloucestershire, the highest temperature ever known in Britain, one full Fahrenheit degree above the previous record, set in 1911.
The United Kingdom heatwave of 1911 was a particularly severe heatwave and associated drought. Records were set around the country for temperature in England, including the highest accepted temperature, at the time, of 36.7 °C (98.1 °F), only broken 79 years later in the 1990 heatwave, which reached 37.1 °C (98.8 °F). A temperature of 100 °F (38 °C) was recorded at Greenwich in a Glaisher stand and was regarded as the record but further data from a Stevenson screen in the same location showed the temperature to be 96.6 °F (35.9 °C). The highest ever accepted temperature is currently 40.3 °C (104.5 °F) recorded on 19th July 2022 on a Royal Air Force station in Coningsby, Lincolnshire. Weather in Northern Europe was also affected around about this time.
The winter of 1990–91 was a particularly cold winter in Western Europe, noted especially for its effect on the United Kingdom, and for two significantly heavy falls of snow which occurred in December 1990 and February 1991. Sandwiched in between was a period of high winds and heavy rain which caused widespread damage. The winter was the coldest since January 1987, and the snowfall experienced in many parts of the United Kingdom would not be seen again until the snowfall of February 2009.
Güzelhisar Dam is a dam in Izmir Province, Turkey, built between 1975 and 1981. The development was backed by the Turkish State Hydraulic Works.
A megadrought is an exceptionally severe drought, lasting for many years and covering a wide area.
The 2018–2021 Southern Africa drought was a period of drought that took place in Southern Africa. The drought began in late October 2018, and negatively affected food security in the region. In mid-August 2019, the drought was classified as a level 2 Red-Class event by the Global Disaster Alert and Coordination System. The alert level was reduced to the Orange-1.7 by 12 December 2019, as the new wet season had started. In September 2020, the drought was classified as a level 2 Red-Class event. The drought continued into early 2021. Beginning in October 2021, South Africa experienced above average rainfall and reservoirs refilled by early 2022.
Drought is common in Turkey, especially in the south and center of the country, with 2021 being the driest in 2 decades. Droughts are forecast to occur more frequently due to climate change, and 2023 began with drought. Most water loss is due to poor irrigation. In 2022 the World Bank said that “without reform, a 10% fall in water supply in Turkey could reduce GDP by 6%”.
The effects of climate change on the water cycle are profound and have been described as an intensification or a strengthening of the water cycle. This effect has been observed since at least 1980. One example is the intensification of heavy precipitation events. This has important negative effects on the availability of freshwater resources, as well as other water reservoirs such as oceans, ice sheets, atmosphere and land surface. The water cycle is essential to life on Earth and plays a large role in the global climate and the ocean circulation. The warming of our planet is expected to cause changes in the water cycle for various reasons. For example, warmer atmosphere can contain more water vapor which has effects on evaporation and rainfall.
A drought developed in the Western, Midwestern, and Northeastern United States in the summer of 2020. Similar conditions started in other states in August 2020, including Iowa, Nebraska and certain parts of Wisconsin and Minnesota. At the same time, more than 90% of Utah, Colorado, Nevada and New Mexico were in some level of drought. Also in drought conditions were Wyoming, Oregon and Arizona.
During the summer of 2022, parts of Europe experienced drought conditions exacerbated by heat waves. On 9 August, a senior European Commission researcher said it seems to be Europe's worst year in 500 years. A report from the Global Drought Observatory has confirmed this. The drought had serious consequences for hydropower generation and the cooling systems of nuclear power plants, as the drought reduced the amount of river water available for cooling. Agriculture in Europe was also negatively affected by the drought.
