Long droughts can be disruptive and dangerous for many sectors including agriculture, water supplies, fisheries, health, and infrastructure. They cause river and reservoir levels to drop, making them particularly straining for farmers. The 1976 drought in the UK made an estimated £3,500 million worth of crops fail. They can also be extremely dangerous – it was drought conditions that allowed the so-called ‘King fire’ of California to spread so quickly in 2014.

One of the challenges of managing droughts is that they are hard to predict. Their long, extended nature means current technology can't give more than one month’s warning.

Their drawn-out nature also means that the term ‘drought’ has no exact definition. The common understanding that droughts are a space of abnormally dry weather isn't very useful as what's ‘abnormal’ changes from one region to the next. Bali is so wet that six days without rain is enough to create a drought, while in Libya it is pretty normal for nearly two years to go by without any rain at all.

CEH Fellow Terry Marsh has written this short blog post which examines "What is a drought?"

A drought’s slippery definition means it is sometimes easier to refer to them by their causes or impacts:

  • hydrological drought - refers to a lack of water in all parts of the water cycle
  • meteorological drought - determined by the number of days without rain
  • agricultural drought -focuses on the amount of water in the soil
  • socioeconomic drought - a lack of water means that demand for an economic good exceeds the supply

CEH work on drought


August 2015 river flows in the UK
August 2015 hydrological summary for the UK
July 2015 river flows in the UK
July 2015 hydrological summary for the UK
Widespread drought-sensitive butterfly population extinctions could occur in the UK as early as 2050
ECN Moor House in the North Pennines
Long-term multi-parameter monitoring to understand causes and consequences of environmental change
Campbell-Stokes Sunshine Recorder at CEH's Wallingford meteorological station
Providing daily data from our met station in Oxfordshire
Austria Center Vienna, photo: CC-BY-SA-3.0 BambooBeast
Details of abstracts from Vienna General Assembly
Weir Photo: Shutterstock
The UK’s focal point for river flow data
Meteorological equipment
Long-term weather monitoring to develop understanding of hydrometeorological systems
River Thames and countryside near Oxfordshire, photo by Shutterstock
A consistent assessment of climate change impacts across Great Britain
Scottish Freshwater Group logo
Promoting collaboration on a wide range of issues related to the freshwater environment - one of Scotland's most precious natural resources
Identifies unit hydrographs and component flows from rainfall, evaporation and streamflow data
Drought cover
Provides estimates of river flows in the UK