Drought as a natural disaster

Droughts are major natural disasters for many parts of the world. Dry areas, where the precipitation pattern is markedly seasonal, or is otherwise highly variable, are the most susceptible. The Canadian Prairies, together with the U.S. Great Plains, are one such area. While immediate loss of life is seldom a feature of most droughts, malnutrition and even starvation do follow severe droughts in some parts of the world. In Canada, economic losses, particularly in the agricultural sector, may reach several hundred millions of dollars in a drought year, with major socio-economic repercussions affecting the entire region. Environmental damages include soil degradation and erosion, vegetation damage, slough and lake deterioration and wildlife loss. Unlike most other natural disasters, drought onset is difficult to identify. Droughts develop slowly, and until human activity begins to be affected by an on-going reduction of precipitation, their existence is unrecognized. Development and applications of specific soil moisture and drought indices based on cumulative precipitation deficits have enhanced drought monitoring programs. These in turn provide guidance on the need for mitigate measures that can be initiated early in the course of a drought.(AU)

Hydrometeorological aspects of flood hazards in Canada

Floods are major disasters in Canada and worldwide. Although technology has reduced the flood hazard in many areas, the world death toll from floods in recent decades still has averaged 4680 per year. During the summer of 1993, flooding in the U.S.A. caused an estimated $12 billion damage. These statistics confirm that floods are a major natural disaster. This paper reviews the hydrometereological aspects of the hazard associated with rainstorm, urban, ice-jam, and snowmelt floods. The hazard element is highest for floods with rapid onsets such as rainstorm, urban, and ice-jam floods. Although snowmelth floods are common throughout Canada, their slower onset times reduce their risk potential. To reduce the risk of the flood hazard, society must have access to statistical information for adequate planning and design, and forecasts for issuing warnings and implementing evacuation strategies. Flood design statistics and forecast models are discussed relative to each major flood type. The paper also describes historical flood frequency trends and discusses the implications of climatic warning for future floods. The paper concludes with a brief discussion of some knowledge gaps and research needs.(AU)

Research implications of the 1988 Canadian prairie provinces drought

The 1988 drought conditions, which prevailed over the southern portion of the Canadian prairie provinces, resulted in severe impacts on agriculture, water resources, forestry, and waterfowl production. In this paper, the climatological aspects of the drought are reviewed and the impacts of the drought are described. IN addition, a number of the environmental factors that may have aggravated the drought's impacts are discussed. In this paper these needs are discussed; several specific hypotheses concerning drought-related processes are advanced and a framework for addressing the scientific aspects of droughts on the Canadian prairies is proposed. It is anticipated that many of these identified research needs and opportunities are applicable to other drought-prone areas of the world (AU)