In Meteorology it is a climatic anomaly that occurs at the poles. Trough, means deep valley, plain, deep canyon, depression of a land through which a river or stream of water flows, canyon, ravine. The polar trough is characterized by very strong winds and extremely cold temperatures, accompanied by rainfall.
The polar trough is a meteorological anomaly that causes an area of low pressure and elongated shape, due to the collision with another area of hot air and that causes hurricane winds, very cold temperatures and heavy rains. It usually occurs in places where there are rivers that run at great depth, surrounded by hills.