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Drought information

Last updated on April 15, 2024

Drought is a recurrent feature of climate involving a deficiency of precipitation over an extended period of time, resulting in a water shortage. Water scarcity is when there is not enough water to meet the needs of people and ecosystems.

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What is drought?

Drought may be caused by combinations of insufficient snow accumulation, hot and dry weather, or delay in rainfall.

Drought can be further defined as meteorological, hydrological, agricultural, socioeconomic and ecological. Each definition implies different impacts.

The Province's drought response focuses on hydrological drought, which is described by:

  • Reduced lake storage
  • Decreased stream flow discharge
  • Lowered groundwater levels

Hydrological droughts occur after a period of dry conditions, which can result in water scarcity. Hydrological drought affects uses that depend on groundwater and stream flows.

Changes in water levels affect:

  • Ecosystems
  • Hydroelectric power generation
  • Recreational, industrial and urban water use

Drought level classification

The Province uses a six-level classification to rate the severity of drought conditions. Provincial drought levels are set following the guidance in the British Columbia Drought and Water Scarcity Response Plan (PDF, 1.2MB). Drought level classification uses core and supplemental drought indicators.

The core indicators are:

  • 7-day average stream flow
  • 30-day precipitation

Some supplemental indicators are:

  • Air temperature
  • Aquifer levels
  • Soil moisture deficits

Drought classification levels state the likelihood of negative socioeconomic and ecosystem impacts. They also provide guidance on anticipated response measures, although regulatory actions can be taken at any drought level.

Drought Level Classification
Level Impacts General Response Measures
0 There is sufficient water to meet socioeconomic and ecosystem needs Preparedness actions
1 Adverse impacts to socio-economic or ecosystem values are rare Conservation actions
2 Adverse impacts to socio-economic or ecosystem values are unlikely Conservation actions including local water restrictions where appropriate
3 Adverse impacts to socio-economic or ecosystem values are possible Conservation actions including local water restrictions where appropriate
4 Adverse impacts to socio-economic or ecosystem values are likely Conservation actions including local water restrictions and regulatory action where appropriate
5 Adverse impacts to socio-economic or ecosystem values are almost certain Conservation actions including local water restrictions, regulatory action and emergency response measures where appropriate

Effects of drought

Impacts to communities and agricultural production

Severe drought conditions pose significant risks to people and communities. Drought can lead to reduced water availability for household and business use. Drought can reduce crop growth and quality, leading to smaller harvests. Less water may be available for irrigation and for animal care. Hotter temperatures that coincide drought may lead to early crop maturity or ripening.

The Province provides advice and drought management tools to those affected by drought and/or loss of water in agriculture.

Impacts to Fish and Aquatic Ecosystems

Drought conditions pose risks to fish and fish habitat. This includes Pacific salmon and other aquatic species at risk. 

Drought impacts fish, fish habitat, and aquatic ecosystems by causing:

  • Dewatering of fish streams
  • Low stream flows
  • High stream temperatures

Drought conditions can lead to:

  • Fish strandings
  • Death of fish
  • Delayed movement of migrating fish into spawning streams
  • Losses in biodiversity

The Province is working with Fisheries and Oceans Canada, First Nations, non-governmental organizations, and others to develop and share information and educational materials. These groups are taking action to support priority fish populations affected by drought.

This work includes:

  • Relocating stranded salmon in dewatered streams
  • Providing or improving fish passage in low flow streams
  • Creating cold water refuge habitats
  • Implementing and enforcing fisheries closures to protect at-risk stocks

During severe drought, the Province works to identify, monitor, and where possible, reduce the impacts of drought on fish, fish habitat, and aquatic ecosystems, particularly in streams that support Pacific salmon or aquatic species at risk.

Specific areas of collaboration include:

  • Establishing watch lists for streams and fish populations at greatest risk of drought impacts
  • Monitoring stream flows, stream temperatures, and fish numbers, distribution, and responses to drought and flow management on watch list and other fish streams
  • Defining critical flow thresholds for watch list watersheds and fish populations at greatest risk due to combined effects of drought and water use
  • Advising when curtailment of water use should be considered to limit impacts

Fish populations that are vulnerable to drought conditions often have significant:

  • Economic, social, and cultural importance to people, including Indigenous Peoples. Examples include chinook salmon, coho salmon, pink salmon, kokanee salmon, bull trout, rainbow trout, and steelhead 
  • Conservation concerns, such as endangered Nooksack dace and Salish sucker

B.C.’s Biodiversity and Ecosystem Health Framework outlines the Province’s commitment to protecting biodiversity. Visit plants, animals and ecosystems to learn more about nature and wildlife in B.C.

Water management during drought

The British Columbia Drought and Water Scarcity Response Plan (PDF, 1.2MB) focuses on hydrological drought and water scarcity response actions taken before, during, and immediately after a drought.

The plan identifies a variety of actions and accountabilities, including:

  • Responsibilities of agencies at the provincial, regional and local level
  • Recommended response actions
  • Response criteria to help decide when to elevate drought responses to higher levels

Low stream flows and hot, dry weather can result in high stream temperatures and the need for angling closures. For more information on angling closures please see Freshwater Fishing Regulations.

Water rights during water scarcity, including drought

Water users are required to use water as efficiently as practicable. When voluntary conservation measures are not sufficient to support all water use on a stream system, or to protect critical environmental flows or the survival of a fish population, the Water Sustainability Act (WSA) provides authority under specified conditions to regulate water diversion use (and storage) by users of both stream water and groundwater. 

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