A flood is an overflow of water that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study in the discipline of hydrology and are of significant concern in agriculture, civil engineering and public health. Human environmental changes often increase the intensity and frequency of flooding, for example, land use changes such as deforestation and removal of wetlands, changes in waterway course or flood controls such as with levees, and more significant environmental issues such as climate change and sea level rise. In particular, increased rainfall and extreme weather events caused by climate change increase the severity of other flooding causes, resulting in more intense floods and increased flood risk.

Flooding may occur as an overflow of water from water bodies, such as a river, lake, or ocean, in which the water overtops or breaks levees, resulting in some of that water escaping its usual boundaries, or it may occur due to an accumulation of rainwater on saturated ground in an areal flood. While the size of a lake or other body of water will vary with seasonal changes in precipitation and snow melt, these changes in size are unlikely to be considered significant unless they flood property or drown domestic animals.

Floods can also occur in rivers when the flow rate exceeds the capacity of the river channel, particularly at bends or meanders in the waterway. Floods often cause damage to homes and businesses if they are in the natural flood plains of rivers. While riverine flood damage can be eliminated by moving away from rivers and other bodies of water, people have traditionally lived and worked by rivers because the land is usually flat and fertile and rivers provide easy travel and access to commerce and industry. Flooding can lead to secondary consequences in addition to damage to property, such as long-term displacement of residents and increased spread of waterborne diseases and vector-borne diseases transmitted by mosquitos.

FLOOD St Andre

Une inondation est une submersion temporaire, naturelle ou artificielle, d'un espace par de l'eau liquide. Ce terme est fréquemment utilisé pour décrire :

• le débordement d'un cours d'eau, en crue puis en décrue, sur les terrains voisins ; l'eau est répandue dans les talwegs et les dépressions topographiques ;

• le ruissellement très important d'origine pluviale, soit sur des terres cultivées (inondation boueuse), soit en zone imperméable urbanisée;

• le débordement ou les conséquences de la rupture d'ouvrages artificiels hydrauliques tels que retenues d'eau, digues, canalisations (agricoles, d'eau potable, d'assainissement) ou la rupture d'une retenue naturelle comme celle d'un lac glaciaire, provoquant une inondation soudaine ;

• la remontée émergente d'une nappe phréatique ;

• l'envahissement temporaire par la mer d'une zone côtière lors d'une submersion marine ou d'un tsunami.

L'inondation est un des principaux risques naturels dans le monde ; c'est la catastrophe naturelle causant le plus de dégâts. Pour la période 1996-2005, environ 80 % des catastrophes naturelles mondiales étaient d'origine météorologique ou hydrologique. Les inondations auraient affecté en moyenne 66 millions de personnes par an entre 1973 et 1997 et elles devraient s'aggraver dans beaucoup de ports et communes littorales: selon une étude évaluant le coût probable de l'élévation des océans et des phénomènes météorologiques extrêmes pour les 136 principales métropoles littorales, les inondations pourraient coûter environ 1 000 milliards par an de 2010 à 2050, rien que pour ces villes.

• Flood OKA 2023

• Flood St Andre 2023

Winter storm

A winter storm is an event in which wind coincides with varieties of precipitation that only occur at freezing temperatures, such as snow, mixed snow and rain, or freezing rain. In temperate continental and subarctic climates, these storms are not necessarily restricted to the winter season but may occur in the late autumn and early spring. A snowstorm with strong winds and other conditions meeting specific criteria is called a blizzard. 

Winter 2007 - 2008

Severe winter weather conditions, called "winter storms," can be local weather fulfilling the criteria for 24 hours or large storm systems covering part of a continent for several days. With large, massive winter storms, weather in any part of the area covered by extreme weather is usually called a "storm," even if meteorological criteria for winter storms are not met everywhere. An example is the February 13–17, 2021, North American winter storm with snowfall and below-freezing temperatures as far south as Texas and the Gulf of Mexico.

Snowstorms are storms where large quantities of snowfall. 2 in (5.1 cm) of snow is enough to create serious disruptions to traffic and school transport (because of the difficulty of driving and manoeuvre the school buses on slick roads). This is particularly true in places where snowfall is not typical, but heavy accumulating snowfalls can occur. In places where snowfall is typical, such small snowfalls are rarely disruptive because of adequate snow and ice removal by municipalities, increased use of four-wheel drive and snow tires, and drivers being more used to winter conditions. Snowfalls over 6 in (15 cm) are usually universally disruptive.