Rapidly intensifying hurricanes and bunched-up tornadoes

Two recent papers in Nature Communications by Columbia researchers focus on properties that emerge when one analyzes the statistical distributions of two different types of severe storms – tropical cyclones and tornadoes. Both highlight the most extreme instances of these already extreme events, and find surprising behavior in both, though in quite different ways.

The first paper, led by IRI postdoc Chia-Ying Lee, focuses on the distribution of lifetime peak intensities reached by tropical cyclones, globally and in individual basins. The distribution is bimodal; there are a lot of weak storms and a lot of intense storms, and fewer middling storms in between. It turns out that the great majority of the intense ones form after at least one round of “rapid intensification”. The full paper is available here, and Francesco Fiondella’s piece on the IRI web page is here.

The second, by Michael Tippett and Joel Cohen, focuses on tornado outbreaks. That is, bursts of tornadoes that come together in a bunch, and the statistics of how many come per bunch. In a year where there are many tornadoes per outbreak on average, there is also much more variability from outbreak to outbreak. This kind of behavior is found in collections of some other kinds of events from very different fields, but not to this degree. The paper is here, and the Earth Institute news piece on it is here.