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Tropical Cyclone

Violent atmospheric anomaly characterized by strong whirling winds accompanied by rain. They are originated in the Caribbean Sea and tropical areas of the Pacific and Indian Oceans. They are known as Hurricanes in the Caribbean and as Typhoons in the West Pacific Ocean.

Tornado

A tornado (also known as twister) is a violently rotating column of air extending between, and in contact with, a cumulunimbus cloud and the surface of the earth. The stronger tornadoes attain very high intensities, with wind speeds that exceed 200 mph and in extreme cases may approach 300 mph. Tornadoes are categorized on a scale of 0 (weakest) to 5 (strongest) according to the Enhanced Fujita Scale.

Storm / Gale

Heavy rain accompanied by strong winds and/or electric discharges (lightning). Due to regional connotations, sometimes there is no difference between “storm” and “gale”.

Extreme Rain

Precipitation. Includes punctual, persistent or torrential rain, or rain exceeding the rainfall averages of a specific region; also, unusual long rain periods. Rain includes terms such as downpour, cloudburst, heavy shower, deluge, etc.

Electrical Storm (also Thunderstorm or Lightning)

Occurrence of atmospheric static discharges (lightning) with effects on people, cattle, domestic properties, infrastructure (power networks, for example, causing blackouts), and the environment. It is different from “storm” in that thunderstorms are not accompanied by rain and gusty winds. The key differentiator is that damage is caused explicitly by lightning.

Hailstorm

Precipitation of hail. Frozen raindrops of varying sizes that fall violently in the form of hard pellets.

Snowfall

Anomalous fall and accumulation of snow, especially when it occurs in zones not subject to seasonal changes. This term refers to events where precipitation exceeds the average multi-annual values, causing especially serious effects.

Cold Wave

Drop of atmospheric average temperature well above the averages of a region, with effects on human populations, crops, properties and services.

Frost

Temperature low enough to cause freezing, with damaging effects on population, crops, properties and services.