DMPQ: Please gave an account of the following in 50 words. a) fissure vent b) Chinook c) Fohn

A fissure vent, also known as a volcanic fissure or eruption fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is often a few meters wide and may be many kilometers long.

Chinook :

It is a local winds in steppe region. On the eastern slopes of the Rockies in Canada and U.S.A. a local wind, similar to the Fohn in Switzerland, called the Chinook, comes in a south-westerly direction to the Prairies and has a considerable effect on the local pastures. It actually comes with the depressions in winter or early spring from the Pacific coast ascending the Rockies and then descending to the Prairies [katabatic wind].     It is a hot wind and may raise the temperature by 5° C within a matter of 20 minutes. It melts the snow-covered pastures and animals can be driven out of doors to graze in the open fields. The agricultural year is thus accelerated. Local farmers welcome the Chinook for frequent. Chinooks [Snow eaters] mean mild winters.


Foehn is a hot wind of local importance in the Alps. It is a strong, gusty, dry and warm wind which develops on the leeward side of a mountain range. As the windward side takes away whatever moisture there is in the incoming wind in the form of orographic precipitation, the air that descends on the leeward side is dry and warm (Katabatic Wind).The temperature of the wind varies between 15°C and 20°C. The wind helps animal grazing by melting snow and aids the ripening of grapes.



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