Following several years of below-average precipitation, Arizona faced extreme drought during 2002, the driest water year for many parts of the state. Impacts included hundreds of thousands of acres lost to wildfire, water supply emergencies, vegetation and wildlife mortality, and large economic losses in the ranching and tourism sectors. As a result of these impacts, the governor of Arizona created a drought task force (ADTF) in March 2003, and tasked them with creating short and long-term drought mitigation and response plans within one year.

The research presented here highlights preliminary findings of a drought history study in support of the ADTF. Such information is used by ADTF risk assessment groups in order to determine triggers for mitigation and response actions, based on observed hydroclimatic information. We presented our initial drought assessment to lawmakers and the lay public using a “Top Ten questions about drought in Arizona” format. The questions cover important topics and different aspects of drought including history, long term averages, seasonality, interannual and long-term spatial and temporal variability, extremes, and climatic forcing.

We analyzed data for each of the seven Arizona NOAA climate divisions for the period 1895-2002. Preliminary results show three major statewide drought periods: the early 1900s, the 1950s and 1998-present. Drought affecting only parts of the state occurs more frequently, and spatial variability of drought highlights large physiographic differences within the state.