Where stalling weather systems occur the most

What is it about?

This paper defines a "stalling" type of weather system. It is defined as extratropical cyclone which remains near-stationary and produces extreme rainfall. This definition selects weather systems which are particularly impactful as they produce high total rainfall on large scales, which can result in flooding on a large scale. The paper then uses this definition to show where these systems tend to occur, and finds six hotspots, three in each hemisphere. These hotspots are generally located along the east coasts of major land masses, plus the Mediterranean. A link is drawn to East Coast Lows in Australia, Nor'Easters in North America, and similar events off the coast of South America, South Africa, Japan, and in the Mediterranean.

Featured Image

Photo by Steve Gribble on Unsplash

Photo by Steve Gribble on Unsplash

Why is it important?

Some extratropical cyclones not only produce large amounts of rainfall, but they also stall their movement, resulting in high cumulative rainfall and thus flood risk. These are not small storms with very localised impact, but large-scale weather systems with a large impact footprint. While research has been done on such systems in Australia, where East Coast Lows represent a somewhat similar weather type, our research shows that this is a global phenomenon, where eastern coasts of the continents in both hemispheres seem to produce these slow-moving, rain-bearing cyclones.

Perspectives