Drought severity is typically measured on a five-tier classification scale (ranging from D0 to D4) based on the U.S. Drought Monitor framework, which is also adapted internationally.
| Level | What it means |
|---|---|
| D0 (Abnormally Dry) | Short-term dryness that slows plant and crop growth or causes lingering water deficits, technically it’s a pre-drought rather than a full drought. |
| D1 (Moderate Drought) | Some damage to crops and pastures occurs; streams, reservoirs, or wells are low, and voluntary water restrictions may be requested. |
| D2 (Severe Drought) | Crop or pasture losses are likely, water shortages become common, and mandatory or standard water restrictions are imposed. |
| D3 (Extreme Drought) | Major agricultural losses occur alongside widespread water shortages or strict restrictions. |
| D4 (Exceptional Drought) | The most intense level, causing widespread, exceptional crop/pasture destruction and severe water emergencies in streams, wells, and reservoirs. |