As noted by the Wyoming State Climatologist (Jan Curtis):

Wyoming's statewide drought that appeared to begin in earnest in March 2000 had, by the end of October 2002, developed to extreme levels with even an area of exceptional intensity over the central southwest region of the state (as seen in the October 29 U.S. Drought Monitor weekly map).

Analysis of seven-day average streamflows also shows nearly 20 percent of streams at record low flows with an additional 27 percent at the 10 percentile level. This is remarkable considering that all these streams have been measuring flow for well over 30 years.

At the state's only USDA/NRCS SCAN (Soil Climate Analysis Network) station in Torrington, conditions reveal that the soil moisture is extremely dry at depth (below 8 inches) for 2002. The periodic moisture spikes near the surface have not been of a long enough duration and intensity to recharge the soil to greater depths. (The graph depicts the percent of water in the ground, by volume.)

The full fledged hydrological drought within Wyoming will approach a social-economical drought emergency if this winter's snowpack fails to develop.

Graumlich, L.G., M.F.J. Pisaric, L.A. Waggoner, J.S. Littell, and J.C. King, in press. "Upper Yellowstone River flow and teleconnections with Pacific Basin climate variability during the past three centuries." Climatic Change.

The NOAA Paleoclimatology Branch provides the data and description.