RESUMO
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)