National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI)
The North American Drought Monitor (NADM) is a cooperative effort between drought experts in Canada, Mexico and the United States to monitor drought across the continent on an ongoing basis. The program was initiated at a three-day workshop in late April 2002 and is part of a larger effort to improve the monitoring of climate extremes on the continent. The NADM (Lawrimore et al. 2002) is based on the highly successful U.S. Drought Monitor (USDM), and as such, is being developed to provide an ongoing comprehensive and integrated assessment of drought throughout all three countries.
North American Drought Monitor - Indices and Data include: “Standard Precipitation Index (SPI),” “Percent of Average Precipitation” and “Palmer Drought Severity Index (PDSI)”