The Drought Information Center metasite serves as a gateway to NOAA's (and other) online resources on drought and climate conditions. From the US Drought Monitor (current assessment of drought status), to the Palmer Drought Severity Index, to paleo perspectives on North American drought, this site covers background information, current updates, and future predictions on droughts.
The NOAA Paleoclimatology Program is responsible for this excellent resource on Drought in North America, described within a geological timescale. Specifically, the Website aims "to explain how paleoclimatic data can provide information about past droughts and about the natural variability of drought over timescales of decades to millennia." The site is organized into four main sections: The...