Weather warning side companies like Weather Watch or Instant Weather. These side companies are not associated with the government in any way. Environment Canada defines a advisory as ""an alert to cover a wide array of deteriorating weather conditions,"" a watch as ""when conditions favour that severe weather forming"" and a warning as ""severe weather is actually occurring or is imminent."" . Additionally, Environment Canada breaks down weather alerts based upon the specific type of hazardous weather. These alerts are regionally issued throughout Canada and include, but are not limited to, winter storms, extreme temperature, ice, thunderstorms (including tornadoes), wind, tsunami, tropical
Foehn wind it expands and cools due to the decrease in pressure with height. Since colder air can hold less water vapour, moisture condenses to form clouds and precipitates as rain or snow above the mountain's upwind slopes. The change of state from vapour to liquid water is accompanied by heating, and the subsequent removal of moisture as precipitation renders this heat gain irreversible, leading to the warm, dry foehn conditions in the mountain's lee. This mechanism has become a popular textbook example of atmospheric thermodynamics and it lends itself to attractive diagrams. However the common occurrence of 'dry' foehn events, where