With the recent ef0 tornado in Montgomery county Maryland, this past weekend, I wanted to explain how one forms, talk about how often tornadoes impact our area and lastly, explain the difference between tornados, Gustnadoes, dust devils and waterspouts. For starters, tornadoes don’t just form out of nowhere, they instead develop out of strong to severe thunderstorms. When one forms, there are already ingredients in place, like a steady upward flow of warm air, to get things started. Similar to a sporting event, when there is action going on, but then a home run is hit or a hockey puck hits the net, the crowd suddenly erupts into pandemonium. Well in mother nature’s case, conditions are already volatile before a tornado forms; they just escalate into something even more serious. To continue with the sports analog, “The players” that are needed to get it all started are: heat, moisture, instability, wind shear, and sometimes a forcing mechanism ( I.E. Cold front). Thunderstorms form like other clouds, but if the air continues to rise, this cloud will continue to accumulate an enormous amount of energy.
What happens over time, is that a change in wind direction is needed to be in place, between ground level and 30,000 feet above our heads, called wind shear,. is key in developing a tornado. So basically the change in wind direction with height causes horizontal rotation, into strong vertical wind as the air is lifted up into the thunderstorm, and the beginnings of a tornado are forming. Air that spins as it rises is typical in a supercell, the strongest type of thunderstorm, but not all spinning air creates a tornado, as I’ll talk about in a bit. Just like the EF0 Poolesville, Maryland tornado, not all tornadoes are large and stay on the ground for 30 minutes. Smaller tornadoes may only thrive for a matter of minutes, covering less than a mile of ground. Wind speeds vary from smaller, short-lived to larger long-lasting tornadoes, as the enhanced Fujita scale shows us. A EF rating starts at 0 and goes to 5 with the weakest winds beginning at 65 mph and the strongest exceeding 200 mph! At this point, you might be wondering how tornadoes eventually dissipate. Believe it or not, there is still some debate within the scientific community, to how these deadly storms die, but one thought is that the parent thunderstorm could be possible contributor to its demise.
As I mentioned earlier, multiple ingredients are needed to create a tornado, and if you disrupt or take away just one of those “Ingredients”, well then you take its survival rate and it can’t function. Often, a tornado will die because the cold outflow of air from falling precipitation upsets the balance. Tornadoes can and have occurred in just about every U.S. State, but certainly they favor places that contain hot, humid air, plenty of moisture and wind shear. Those states are in the central and southeast U.S. And because tornadoes frequently return year after year in these states, they are referred to an area of the country called “Tornado alley”. Locally, since 1950, Maryland has seen over 400 tornadoes throughout the state. In northern Virginia, 143 events were reported and in the eastern panhandle of West Virginia 165 reported, according to NOAA’s storm events database. Compared to Texas, these numbers are small, but we do hold all the necessary ingredients to create one of nature’s most dangerous types of storms.
So now that you know how tornadoes form and where they generally form, how do they compare to other storms that they are related too? Those other storms are waterspouts, Gusnadoes and dust devils. Those other storms are waterspouts, Gusnadoes and dust devils. Unlike tornadoes, these three do not form based on rotating updrafts, but there is a catch when it comes to waterspouts. Waterspouts can occur two ways and are referred to in two different ways. Tornadic waterspouts are simply tornadoes that form over water or move from land to water, occurring with afternoon and evening thunderstorms, but fair-weather waterspouts form during relatively calm weather and with no thunderstorms in the area. They typically occur during light wind conditions and because of this, these waterspouts don’t move much. Unlike tornadic waterspouts, which tend to happen in the afternoon, fair-weather waterspouts typically occur in the early to mid-morning hours, and sometimes in the early afternoon. Everyone associates tornadoes and waterspouts with thunderstorms, but in a fair-weather waterspout, there are no thunderstorms in the area. According to the national weather service, dust devils are dust-filled spirals that are created by steady surface heating and similar to fair-weather waterspouts are relatively harmless. Dust devils form in areas of strong surface heating, as they generally form under clear skies and calm winds, when the ground can heat the air to temperatures above that of the ground. A Gustnado forms within the downburst emanating from a thunderstorm, as Gustnadoes form due to non-tornadic straight-line wind features in the downdraft (outflow), specifically within the gust front of strong thunderstorms. Gustnadoes tend to be noticed when they loft sufficient debris into the air, similarly to tornadoes, but these storms very rarely connect from the surface to the cloud base, which tornadoes do. The Gustnado has little in common with tornadoes in development, intensity and longevity.
As you can see, mother nature is not to be messed with, as “She” can create something out of apparently nothing in literally seconds. Nature is powerful and as man has gotten better in capturing the awesome sights and sounds of these amazing natural wonders, it has created a curiosity beyond all comprehension. That is why I have hopefully conveyed the important information on some of the most feared weather systems alive.