A polar low is a small sized and short-lived atmospheric low pressure system that is found over the ocean areas pole ward of the main polar front in both the Northern and Southern Hemispheres. The systems usually have a horizontal length scale of less than 1,000 km and live for less than a couple of days. They are part of the larger class of mesoscale weather systems. Polar lows can be difficult to detect using standard weather reports and are a problem to high-latitude operations, such as shipping and gas and oil platforms.