Wind has been in the news lately.
Cyclone Winston became a named storm on February 10th and then spent 12 days blowing around the South Pacific–literally, the storm track curved back on itself and made a big loop, something I personally hadn’t known was possible. It crossed over Fiji as a Category 5 storm, killed 21 people, and literally leveled whole communities–a kind of destruction more typical of powerful tornadoes. At one point, the storm packed sustained winds of at least 186 mph. That’s the most powerful storm ever measured in the southern hemisphere.
Then, on February 23rd and 24th, a swarm of tornadoes swept through the United States, killing at least three and injuring many more. The storms (though not the tornadoes) actually passed over my area, giving us high, gusting winds and thunder. In February.
Of course, some kind of extreme weather probably occurs somewhere on the planet every day. It’s a big planet, after all. But these are both extreme extremes–Cyclone Winston was one of the most powerful tropical cyclones ever measured. And the tornado outbreak was in February. And they both relate to climate change–although, so do all other weather events, extreme or otherwise, since the climate changes on the just and unjust alike. Still, it’s interesting to look at the actual connections.
First, Winston. As I’ve written before, tropical cyclones with sustained winds of 75 mph or more are called different things in different ocean basins and different basins also have different storm seasons, and different storm behavior. In the North Atlantic, these storms are called Hurricanes. Winston was called a cyclone because it existed in the South Pacific where it is now late summer. So if it seems like we’ve heard about the “world’s most powerful storm” rather often recently, that’s in part due to the fact that we’ve had multiple basins turning up extraordinary storms, not multiple records being set and broken in just a few months. Still, we do seem to be seeing a lot of big storms lately.
As I’ve written before also, it is hard to tell for sure if tropical cyclones have been getting worse because we only have a few decades of quality data–and the way meteorologists study these storms vary from one ocean basin to another, too, which means that much of the data we do have cannot be pooled. We know that climate change should be making tropical cyclones stronger, more frequent, or possibly both, because the new climate involves warmer water and more humid air, both of which are what makes tropical cyclones happen–we just can’t actually see the changes yet because of the data problem.
But Winston was actually the result of multiple atmospheric cycles working together. Tom Yulsman write a clear and interesting article explaining these cycles. You can find his article here. To summarize, both global warming and El Niño were involved in the unusually warm water that fed the storm while an even shorter cycle, the Madden-Julian Oscillation, that changes over just weeks, made the atmosphere more stormy at just the right time. Day-to-day weather changes then steered the storm through its bizarre circular track and right over Fiji.
So the simple answer is that yes, while we don’t have the data to confirm it, we can be pretty sure that these record-breaking storms have some degree of extra edge due to climate change–and at the same time, other patterns also influence the situation.
Meanwhile, Cyclone Winston exemplifies another pattern–no matter how strong or weak a storm is, it’s going to be worse for impoverished people. Wealthy people can afford to rebuild and wealthy countries can afford to provide extensive aid. Many of those in Fiji can access neither wealth nor extensive aid–they are literally asking for help from the world. And because Fiji is very small and very far away from many of my readers’ countries, it’s all too easy to forget about them. Please help if you can and spread the word.
As to tornadoes, again we have a serious problem with a lack of quality data. It’s hard to tell whether there are more tornadoes than there used to be when until recently there was no way to tell a tornado had happened unless somebody was there to see it. But recently some researchers have teased out a changing pattern. Apparently, the number of days per year that have tornadoes on average are stead or dropping, but the number of tornadoes per outbreak is going up. That is in keeping with the warmer, more humid air, which should make storms more powerful, and a simultaneous decrease in wind shear, also a result of global warming, which makes tornadoes less likely. So, fewer days when tornadoes can form, but on those few days, the storms are worse.
Tornado swarms in February are rare but hardly unheard of. But what some writers are saying–that the atmosphere is behaving “as though it were May“–is very striking. It’s an acknowledgement that this past week’s storm is part of a pattern that we usually don’t see and it is directly related to warmth. Specifically, the Gulf of Mexico grew unusually warm and did indeed create a kind of weather more typical of a warmer month. Given that the world is warming, these storms are a bad sign of things to come.