The Drought Impact Lines dataset highlights areas that have been physically impacted by drought. All drought impact lines have a drought impact label inside of them to express the longevity of the impact. The impact lines are classified using impact labels as follows: S – Short-Term, typically less than 6 months. L – Long-Term, typically more than 6 months. SL – A combination of Short and Long-Term impacts.

This series of datasets has been created by AAFC’s National Agroclimate Information Service (NAIS) of the Agro-Climate, Geomatics and Earth Observations (ACGEO) Division of the Science and Technology Branch. The Canadian Drought Monitor (CDM) is a composite product developed from a wide assortment of information such as the Normalized Difference Vegetation Index (NDVI), streamflow values, Palmer Drought Index, and drought indicators used by the agriculture, forest and water management sectors. Drought prone regions are analyzed based on precipitation, temperature, drought model index maps, and climate data and are interpreted by federal, provincial and academic scientists. Once a consensus is reached, a monthly map showing drought designations for Canada is digitized. AAFC’s National Agroclimate Information Service (NAIS) updates this dataset on a monthly basis, usually by the 10th of every month to correspond to the end of the previous month, and subsequent Canadian input into the larger North American Drought Monitor (NA-DM). The drought areas are classified as follows: D0 (Abnormally Dry) – represents an event that occurs once every 3-5 years; D1 (Moderate Drought) – represents an event that occurs every 5-10 years; D2 (Severe Drought) – represents an event that occurs every 10-20 years; D3 (Extreme Drought) – represents an event that occurs every 20-25 years; and D4 (Exceptional Drought) – represents an event that occurs every 50 years. Impact lines highlight areas that have been physically impacted by drought. Impact labels specify the longitude and magnitude of impacts. The impact labels are classified as follows: S – Short-Term, typically less than 6 months (e.g. agriculture, grasslands). L – Long-Term, typically more than 6 months (e.g. hydrology, ecology).

The Drought Impact Label dataset is used on all drought polygons from D1 to D4 to specify the longitude and magnitude of impacts. Impact labels are often used in association with the Drought Impact Line dataset. The impact labels are classified as follows: S – Short-Term, typically less than 6 months. L – Long-Term, typically more than 6 months. SL – A combination of Short and Long-Term impacts.

Forest Drought Risk Assessment Tool (ForDRAT) provides estimates of stand-level drought risk for various BC tree species (Interior only at this point). Drought risk estimates are provided across different biogeoclimatic units and relative soil moisture regimes for both current and future climates. The data are currently provided in a spreadsheet, with the following columns: 1. BGC: Biogeoclimatic zone, subzone and variant. 2. Period: Data are provided for three historical periods: (i) 1961-1990 climate normal period; (ii) 1971-2000; and (iii) 1981-2010. Projected drought risk is provided for three future periods: (i) 2020 (2011-2040); (ii) 2050 (2041-2070); and (iii) 2080 (2071-2100). 3. SMR_text: Text description of relative soil moisture regime. 4. SMR: Integer code of relative soil moisture regime. 5. AET_PET: Mean annual ratio of actual to potential evapotranspiration. 6. The remaining columns provide estimated drought risk by species. Species codes are as follows: (i) Pl = lodgepole pine; (ii) Sx = hybrid white spruce; (iii) Fd = Douglas-fir (interior variety); (iv) Bl = subalpine fir; (v) Cw = western redcedar; (vi) Hw = western hemlock; (vii) Lw = western larch; (viii) Py = ponderosa pine; (ix) Ac = black cottonwood; and (x) At = trembling aspen. More species will be added over time. Details on ForDRAT development are provided in the following resources: DeLong et al. 2022: http://library.nrs.gov.bc.ca/digipub/Tr141.pdf DeLong et al. 2019: https://www.for.gov.bc.ca/hfd/pubs/Docs/Tr/TR125.pdf Foord et al. 2017: https://www.for.gov.bc.ca/hfd/pubs/Docs/En/En119.htm Nitschke and Innes. 2008: https://www.sciencedirect.com/science/article/abs/pii/S0304380007004061?via%3Dihub

The Standardized Precipitation Evapotranspiration Index (SPEI) is computed similarly to the SPI. The main difference is that SPI assesses precipitation variance, while SPEI also considers demand from evapotranspiration which is subtracted from any precipitation accumulation prior to assessment. Unlike the SPI, the SPEI captures the main impact of increased temperatures on water demand SPI values indicate the number of standard deviations the observed anomaly departs from the long-term period of record, with positive values corresponding to wetter-than-average conditions. Time periods calculated for monthly precipitation percentiles are 1, 2, 3, 6, 9, 12, 18, 24 months. Each ISO week is numbered from 1 to 52 (sometimes 53) within a year. An ISO week starts on Monday and ends on Sunday. Historical record goes back to 1980 Indices values were calculated using the xclim python package The National Agroclimate Series of Derived Indicators (NASDI) products provide a collection of comprehensive and regularly updated datasets on key agroclimatic variables, including accumulated precipitation, standardized precipitation index, and difference from normal temperature, among others. These datasets incorporate both real-time and historical climate information, offering enhanced insight into conditions and trends across Canada’s diverse agricultural regions.

Climatic variability plays a critical role in shaping Canada’s agricultural sector, influencing essential factors such as water availability, soil health, and both the yield and quality of crops. Shifts in temperature, distribution of rainfall, and increases in extreme weather events can severely disrupt agricultural operations, making continual environmental monitoring crucial. Canada’s vast and diverse agricultural regions require specialized, localized data to enable effective preparedness and resilience planning for farmers, policymakers, and rural communities; particularly in anticipating and managing drought and other climate-related risks. To address this need, National Agroclimate Series of Derived Indicators (NASDI) products provide a collection of comprehensive and regularly updated datasets on key agroclimatic variables, including accumulated precipitation, standardized precipitation index, and difference from normal temperature, among others. These datasets incorporate both real-time and historical climate information, offering enhanced insight into conditions and trends across Canada’s diverse agricultural regions.

Percent of average precipitation represents the total amount of precipitation for a particular location over a specific time period, divided by the long-term average precipitation (1991-2020) for the same period and location, expressed as a percentage. Percent of average precipitation is to provide a clear and standardized way to compare how much precipitation has fallen during a specific time period relative to the long-term average for the same location and time period. Time periods calculated for monthly precipitation percentiles are 1, 2, 3, 6, 9, 12, 18, 24 months. Each ISO week is numbered from 1 to 52 (sometimes 53) within a year. An ISO week starts on Monday and ends on Sunday. Long-term average is 1991-2020. The National Agroclimate Series of Derived Indicators (NASDI) products provide a collection of comprehensive and regularly updated datasets on key agroclimatic variables, including accumulated precipitation, standardized precipitation index, and difference from normal temperature, among others. These datasets incorporate both real-time and historical climate information, offering enhanced insight into conditions and trends across Canada’s diverse agricultural regions.

Precipitation percentiles represents the accumulated precipitation (mm) for the time period compared to historical information for the same time period. This comparison ranks the current precipitation amount and assigns it a percentile value based on a historic record. Time periods calculated for monthly precipitation percentiles are 1, 2, 3, 6, 9, 12, 18, 24 months. Each ISO week is numbered from 1 to 52 (sometimes 53) within a year. An ISO week starts on Monday and ends on Sunday. Historical record goes back to 1980. The National Agroclimate Series of Derived Indicators (NASDI) products provide a collection of comprehensive and regularly updated datasets on key agroclimatic variables, including accumulated precipitation, standardized precipitation index, and difference from normal temperature, among others. These datasets incorporate both real-time and historical climate information, offering enhanced insight into conditions and trends across Canada’s diverse agricultural regions.

Difference from Average Precipitation represents the accumulated precipitation value for a location, subtracted by the long-term average value. A negative value indicates that the location has received less than the normal amount of precipitation (mm) for that timeframe. A positive value indicates that the location has received more than the normal amount of precipitation (mm). Time periods calculated for difference from average precipitation are 1, 2, 3, 6, 9, 12, 18, 24 months. Long-term average is 1991-2020. Each ISO week is numbered from 1 to 52 (sometimes 53) within a year. An ISO week starts on Monday and ends on Sunday. The National Agroclimate Series of Derived Indicators (NASDI) products provide a collection of comprehensive and regularly updated datasets on key agroclimatic variables, including accumulated precipitation, standardized precipitation index, and difference from normal temperature, among others. These datasets incorporate both real-time and historical climate information, offering enhanced insight into conditions and trends across Canada’s diverse agricultural regions.

The Standardized Precipitation Index (SPI) is widely regarded as one of the most accessible tools for quantifying and reporting meteorological drought. At shorter timescales, SPI values are highly correlated with soil moisture, while at extended timescales, they reflect variations in groundwater and reservoir storage. The SPI model derives probability distributions from historical precipitation records, which are then normalized using an incomplete gamma function across multiple timescales. SPI values indicate the number of standard deviations the observed anomaly departs from the long-term period of record, with positive values corresponding to wetter-than-average conditions. Time periods calculated for monthly precipitation percentiles are 1, 2, 3, 6, 9, 12, 18, 24 months. Each ISO week is numbered from 1 to 52 (sometimes 53) within a year. An ISO week starts on Monday and ends on Sunday. Historical record goes back to 1980 Indices values were calculated using the xclim python package The National Agroclimate Series of Derived Indicators (NASDI) products provide a collection of comprehensive and regularly updated datasets on key agroclimatic variables, including accumulated precipitation, standardized precipitation index, and difference from normal temperature, among others. These datasets incorporate both real-time and historical climate information, offering enhanced insight into conditions and trends across Canada’s diverse agricultural regions.