The term "Palmer Drought Index" has been used collectively to represent multiple indices. This index is simply a water balance model which analyzes precipitation and temperature, and used as a tool to measure meteorological and hydrological drought across space and time. All versions of the index uses the Versatile Soil Moisture Budget to model the movement of water within the system, and a daily Priestly-Taylor model to estimate evapotranspiration. The Palmer Drought Index (PDI) uses monthly temperature and precipitation data to calculate a simple soil water balance. The index is a relative measure that typically ranges from -4 (extremely dry) to +4 (extremely wet) and represents how soil moisture availability differs from that expected for a given place and time of year. The PDI includes a "memory" component that considers past conditions and persistence of soil moisture surplus or deficit.The Palmer Hydrological Drought Index (PHDI) is a specific version of the PDI that accounts for longer-term drought that reduces surface and groundwater supply.

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; andD4 (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 term "Palmer Drought Index" has been used collectively to represent multiple indices. This index is simply a water balance model which analyzes precipitation and temperature, and used as a tool to measure meteorological and hydrological drought across space and time. All versions of the index uses the Versatile Soil Moisture Budget to model the movement of water within the system, and a daily Priestly-Taylor model to estimate evapotranspiration.The Palmer Drought Index (PDI) uses monthly temperature and precipitation data to calculate a simple soil water balance. The index is a relative measure that typically ranges from -4 (extremely dry) to +4 (extremely wet) and represents how soil moisture availability differs from that expected for a given place and time of year. The PDI includes a "memory" component that considers past conditions and persistence of soil moisture surplus or deficit. The Modified Palmer Drought Index (PMDI) is obtained from the sum of the wet and dry terms weighted by probability values. The PMDI has the same value as the PDI during established dry or wet spells but can be different during transition periods.

This data represents the dryness of the land surface based on vegetation conditions. The data is created weekly and uses weekly information on precipitation anomalies (namely the Standardized Precipitation Index or SPI) and satellite vegetation condition derived from Normalized Difference Vegetation Index (NDVI) from the MODIS Satellite. These dynamic data sets along with static data sets on land cover, soil water holding capacity, irrigation, ecozones and land surface elevation are used to model the drought severity, based on the Palmer Drought Severity Index (PDSI). The mapcubist model was trained on historical data and applied in real time to the dynamic inputs to produce drought severity ratings. The model is run at a 1km resolution and was developed by the AAFC, the United States Geological Survey and the United States Drought Monitor at the University of Nebraska Lincoln.

The Blended Index (BI) is a model which employs multiple potential indicators of drought and excess moisture, such as the Palmer drought index, rolling precipitation amounts and soil moisture, and combines them into a weighted, normalized value between 0 and 100. The inputs and weights used in this model are subject to change periodically as it is optimized to best represent extent, duration and severity of impactful weather conditions. The blended index is deployed as two variations; short term (st) focusing on 1 to 3 months, and long term (lt) focusing on 6 months to 5 years.

The Blended Index (BI) is a model which employs multiple potential indicators of drought and excess moisture, such as the Palmer drought index, rolling precipitation amounts and soil moisture, and combines them into a weighted, normalized value between 0 and 100. The inputs and weights used in this model are subject to change periodically as it is optimized to best represent extent, duration and severity of impactful weather conditions. The blended index is deployed as two variations; short term (st) focusing on 1 to 3 months, and long term (lt) focusing on 6 months to 5 years.

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.

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.

The Special Area dataset is comprised of all the polygons that represent Special Areas in Alberta. Special Area is a rural municipality type defined under the authority of the Municipal Government Act. Special Areas were established under the Special Areas Act in 1938 due to extreme hardship of the drought years of the 1930s. The Special Areas Act of 1938 has more or less remained intact although there were some amendments in 1966 and 1985. Special Area refers to a rural area in southeast Alberta.

Shows sub-basin-averaged precipitation from the GEPS ensemble, reflecting the mean (or other metrics) of multiple ensemble members. Useful to understand probabilistic rainfall/snowfall expectations for each watershed.GEPS is ECCC’s ensemble system, running ~20 members globally to quantify forecast uncertainty out to ~16 days. This layer aggregates ensemble precipitation data over sub-basin polygons. The attribute “Average Accumulated Precipitation” often represents the ensemble mean, capturing a more probable average scenario. Operators can use this for risk-based hydrological planning or to gauge confidence in upcoming flood/drought scenarios across different sub-basins.