Is there a good side

to severe storms?


Chuck Doswell

Most recent update 18 June 2008: made some more minor revisions

NOTICE - Any duplication, electronic or otherwise, of the images at this Website without my expressed permission is a copyright violation, and I will treat it as such. Do us both a favor and ask me for permission before using any of the images herein - you can e-mail me at [use the email hyperlink directly or cut and paste the address and replace the "#" with "@"]

NOTICE - All images I show on my Web pages have been scanned from original transparencies, usually with some digital enhancement (touch-ups of dirt on the slides when scanned, and some enhancement of the original scanned images to make them look more like the originals). I don't alter my images digitally to put in things that were not originally in the image, and I don't make digital composites. I'm personally opposed to such image manipulations unless they're admitted to clearly and obviously.

Some recent events have brought to my attention the fact that we severe weather scientists have focused primarily on the "doom and gloom" side of hazardous weather. There are several reasons for this, not the least of which is that the public's perceived need to support our science is in direct proportion to their concern for the phenomena we study. If no one cared about tornadoes, hurricanes, thunderstorms, floods, blizzards, etc., would anyone pay us to study these storms? Probably not.

Another reason for this is that we weather scientists are concerned that many folks have an inappropriately lackadaisical attitude about hazardous weather. At times, it seems to us that the public doesn't worry enough about their own safety to take the simple steps necessary to be prepared. This suggests to some of us that we need to sell the hazards produced by severe storms very aggressively.

However, there's a segment of the public that's irrationally afraid of severe weather (i.e., has a phobia about it), and our "doom and gloom" pronouncements can have the unintended side-effect of augmenting those irrational fears. Thus, I'd like to put out for consideration a number of thoughts that can be used to offset the negative aspects of severe storms that we tend to emphasize.

1. Thunderstorms are the predominant form of precipitation:

during the warm season in middle latitudes. In the tropics and subtropics, virtually all precipitation comes from thunderstorms. What this means is that in order to have any rain at all, we have to endure thunderstorms during the warm part of the year in midlatitudes. Thunderstorms provide the primary rain-producing process in a significant part of the world. Without the beneficial rainfall from thunderstorms, the world would be a much drier and less hospitable place. It's likely that the benefits associated with rain from thunderstorms far outweigh the hazards (wind, hail, tornadoes) that thunderstorms produce. Even in "tornado alley" ... when you have no thunderstorms, you're likely experiencing a drought.

2. Any ordinary thunderstorm produces lightning:

which certainly can be dangerous. However, lightning has a beneficial side-effect that few people recognize. The air is about 78% nitrogen and plants use nitrogen as part of photosynthesis. However, the nitrogen in the air is in a form that plants can't use directly. Lightning, as it turns out, converts some of the air's nitrogen into a form useful to plants, called "fixed" nitrogen. Some plants have "nitrogen-fixing" bacteria that live within their roots and so don't need this help, but most plants don't have the benefit of this symbiosis between themselves and bacteria, so they need help in obtaining nitrogen in a form they can use. Rain falling from thunderstorms actually contains a sort of "free fertilizer"! Real rainfall always seems more beneficial to plants than spreading "artificial" rain from our faucets - perhaps one of the reasons for this is this fertilizing affect associated with thunderstorms.

Furthermore, lightning-caused forest and prairie fires:

are increasingly being recognized as important components of a healthy ecosystem. Plants and animals of this world have evolved in the presence of these fires - some even depend on the fires set by lightning to spread. Although individual plants and animals certainly can be harmed by these fires, the overall ecosystem actually benefits from, and depends on them! Visit a "managed" forest (like a pine tree farm) and you'll find very little life in it apart from the trees - a natural forest is "pruned" from time to time by lightning-caused fires (and other natural processes). The ecological "niches" created by this process make the forest rich with diverse lifeforms that are necessary to a stable ecology.

3. Strong winds from thunderstorms:

can do significant damage to buildings and other artificial structures. However, in the "natural" world outside of human habitations, these seemingly destructive winds have a role to play in the ecology not unlike that of fires (see previous entry). Winds tend to seek out the weak and old parts of a forest, breaking limbs and uprooting some trees. This creates "holes" in the forest canopy, similar to those created by forest fires. Within these gaps in the forest, new plants can prosper that would otherwise be shut out by the impenetrable forest canopy. It is the creation of these gaps in the forest by winds (as well as fires) that makes the forest as a whole prosper by having so much diversity of plants and animals. The most extreme thunderstorm winds, of course, are tornadoes:

As with non-tornadic winds, their paths of destruction in a non-human world may be valuable in creating disruptions to the environment that favor certain plants and animals. In spite of the hazards associated with strong winds and tornadoes, they may well have an important role to play in the planetary ecosystem (see below).

4. Like thunderstorms, hurricanes (tropical cyclones) can bring beneficial rains as well as destruction. It's been found that in drought years, hurricanes are often the process that breaks the drought along their path. Although hurricanes do their worst damage at landfall, they often persist inland in weakened form for great distances as producers of heavy rains. As with thunderstorms, it's possible that the drought-breaking rainfall brought by dissipating hurricanes can offset most of the damage they do. They also are a natural component of the ecosystems along coastlines where they make landfall, and so have a role to play in controlling that landscape. We humans usually find that change destructive, but it's been a part of the world's processes for millions of years. Life has adapted to it and might even depend on it in ways we don't comprehend.

5. Since most atmospheric scientists admit that they don't understand the atmosphere in its entirety, there may be important benefits to storms of all sorts that we presently don't know anything about. It might be that if we could suppress all tornadoes, for example, our winters might be colder or snowier. Or our summers might be hotter and drier. What we know about the atmosphere indicates pretty clearly that all the processes in it are connected to all the other processes in a complex web that we have just begun to comprehend. And the atmospheric processes are tied to things going on in the ocean and even in the solid earth. The very composition of the atmosphere shows that it has been created in its present form by life itself - the high percentage of oxygen comes from plants consuming carbon dioxide and releasing oxygen. With all of the living things tied to the non-living parts of the planet in exceedingly complex ways that we see only very dimly at best, who would want to change things without knowing what the consequences would be? Even if we could prevent hazardous weather somehow (and we surely are not anywhere close to being able to do so!), the consequences of changing things might be far worse than the hazards posed by the weather. We don't know for sure what those consequences are, and the stakes are high if we make a serious mistake. The planet could be transformed by our actions into a place where we would be hard-pressed to survive at all. We humans have a pretty poor track record when we change our environment very much!

There are many things that some (or all) of us find unpleasant about the non-human world around us - mosquitoes, poisonous snakes, wildfires, tornadoes, earthquakes, diseases, and so on. Yet all of these things that we find unpleasant are virtually certain to have a place in a complex natural world. When we humans come into contact with these aspects of nature, we often see them as pure dangers, and even evil. This is not a rational view of our planet. Earth offers no guarantees to individuals, but life on our planet depends on all other life and on the entire non-living planetary structure, as well, for its very survival. What's harmful to individuals is beneficial or even necessary to the majority. All that science has learned tells us that things on the planet, living and non-living, are joined, whether we understand those connections in detail or not. There is nothing evil about such things as animal predators and hazardous weather - they are simply parts of a monumentally complex system that depends on all of its parts to function properly. If we find them scary or ugly, that's simply because they're doing their job. It's our job to stay away from them, and a certain amount of fear is nature's way of helping us be successful in avoiding them. But fear that's irrational - out of control -often leads to errors in judgment that typically increase our chances of making a bad decision; blind panicky terror actually increases the odds that we'll become victims, rather than continue on as survivors.

Finally, some of us find beauty in atmospheric processes, including severe storms. For us, they can be awesome in their grandeur and power,

sublime in their appearance,

and inspirational in their complexity.

Severe storms reveal the human place in nature to those who take the time to observe and to ponder; not humans apart from nature - rather, humans a part of nature. Perhaps many of us were frightened of thunderstorms as children, but some of us have moved away from that fear by trying to learn and have been captivated ever since. For us, storms are to be respected for their hazards but they represent a natural spectacle that's endlessly different, with common threads that form a basis for our present understanding. Storms are neither malevolent nor benevolent - they're simply part of a system that's grand far beyond our human understanding. If severe storms interfere, even violently, with our lives occasionally, they're also an essential part of the world's workings that make our Earth a place where humans can live and thrive.