ABSTRACT
Drought is one of the least understood of the natural hazards and also one of the costliest (Wilhite 2000; National Climatic Data Center [NCDC] 2011). Having an early indication that drought will develop or intensify is critical to employing timely strategies that can mitigate and reduce its impacts. In its most basic form, drought can be thought of as insufficient water to meet demand. Demand can be based on ecosystem processes or on institutional and economic systems linked to human health and welfare. Because understanding demand is critical, systems designed to provide early warning of drought ideally should be able to evaluate changes in both the demand for, and supply of, water and successfully communicate the information to groups or institutions that can apply drought risk reduction strategies.
