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2011 had some of the highest death tolls since the 1920's, when there weren't any modern systems of detection and warning.
I think the real reason that recent death tolls have been high (including 2011) has nothing to do with any real change in the tornadoes themselves…but with the expanding population and changing demographics and human geography in the USA. There are more towns/people/buildings/cars…etc these days in harms way than there EVER was before. This is the same issues with tropical cyclone landfalls in the USA – increasingly there are less and less areas that are rural and empty.
If you look at the tornadoes themselves, the biggest, longest lasting, longest tracked, and most number of tornadoes in each outbreak....the last 20 to 40 years (both warm and cold) have been mild:
Of the top 10 largest “outbreaks” with the largest number of tornadoes (a gauge of how severe the outbreak was) – with the exception of the Nov 21 – 23 , 1992 outbreak, all occurred before 1980…
The longest track (path length) and duration (time on the ground) of tornadoes in the last 20 to 30 years is nothing compared to decades past. Each of the tornadoes in OK this week had a path length of likely less than 5 miles, and lasted for 10 minutes….the 1925 Tri-State Tornado had a path length of 217 miles – and stayed on the ground for six and half hours, through 9 states, killing 700 people and injuring 10,000 (in the rural 1920’s Midwest).
But didn't the last few years seem unusually high in tornado destructiveness?
Yes but just remember, in the 60s we didnt have internet, twitter, facebook, storm chasers, even TVs were starting to become the normal household item. We only had Polaroid cameras I believe. No digital cameras then. Point is, its MUCH more easier to "see" the destruction now and within minutes mind you. Add all that and the population/structure factor and it will seem more destructive recently.
Quote:
Originally Posted by Patricius Maximus
Yes, especially during the age of tornado warnings and so forth. 2011 had some of the highest death tolls since the 1920's, when there weren't any modern systems of detection and warning.
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Another good debate is this. Is population contributing, is a neive society to weather, is it the warning system & radars, is it the actual climate. This chart goes against my population theory but totally supports a better warning system in place with our technology..
Also..... most importantly... keep in mind, a Tornado is measured by the damage it causes.
Let me repeat that.
A Tornado is categorized and measured by the damage within its path. If there are no structures and a Tornado cuts a path through a prarie or open farm land and there were no structures or damage, its considered an EF0 even if technically it was 200mph or EF4 winds.
So think about that.... we could of had a ton of EF4s and 5s before we started building but because there's no way to measure the wind speed and damage, there's no way of knowing how strong it was.
Yes, there have been many more historic snows than is typical for one season.
Well, everything is bigger in Texas, even snowfall. When we can reasonably say the season is over for most of the continent, say around Memorial Day, I might look back and compile a list and description of the significant snows of 2012-13. I can guarantee you that such a list would be pretty eye-popping.
Hmm...it looks like more cold than warm, but at the same time it's nothing notable. I find it curious that the Great Lakes are in a patch of warmer than normal temperatures for May 1-19, just like they were in the first week of the month.
I assume that means code orange? That kind of air quality is horrendous, unsuitable for going outside and enjoying it. Unfortunately, poor air quality is linked to hot weather in most of the U.S.
It's definitely summer where you live, but not in most of the continent. The onset of summer weather varies depending on where you are.
I encourage those who are experiencing a summery weather pattern to transition over to the summer thread. Miamihurricane can start posting in the summer thread in May, and someone in Newfoundland could post about the June snowfall in this thread.
Indeed. I use a "love the sinner, hate the sin" approach to tornadoes - the tornadoes themselves are awesome, but the death and destruction is awful.
If you take the area flattened by tornadoes since 1850, you would find that it comprises a tiny fraction of the area of tornado alley. A given area can go centuries without being flattened, but occasionally an area gets flattened twice in 15 years, like Moore in 1999 and 2013. Hurricanes are more problematic, since they impact a much wider area than a tornado, and they come with storm surge, which is a huge problem for these huge beachfront towers we've foolishly built.
Great. There could be some frosted rooftops.
Yes, especially during the age of tornado warnings and so forth. 2011 had some of the highest death tolls since the 1920's, when there weren't any modern systems of detection and warning.
Tornadoes rely on temperature contrast and wind shear; cold upper levels and stronger storm systems help produce them, assuming that the low-level heat is present. That's why you see tornadoes in the mid latitudes as opposed to the tropics - tornadoes are not a phenomenon driven by heat alone. Case in point: 2012 was the hottest Spring on record in a good chunk of the country, but it was an inactive year, whereas the much cooler Spring of 2011 was very active. Conversely, the Spring of 2013 was the coldest of the three and was very inactive, at least until now; it seemed that instead of tornadoes we got snow . Cooling would seem to produce more favorable conditions for tornadoes in the U.S., but too much cooling would render it too cold for tornadoes to form. Perhaps the 1970's presented a favorable intensity of cooling? At any rate, there is a large amount of annual variation regardless of the general trend, and as we see in this so-far inactive season, it only takes one strong tornado to cause big-time destruction.
As for Cambium's chart, it does present some useful data, but I always think the data would be much more useful if we had 1000 years of modern records to look over. We would have a much better understanding of cycles of climate change than we do now with just one cooling period and one warming period to look at.
well big tornadoes need what u said but smaller ones like the ones here in Florida do just fine with the shear provided by our sea breezes which is why we are one of the most active states when it comes to tornadoes we avg about 50 a year.
Another summer weather phenomenon has appeared in the past few days: clouds of mosquitoes. Good thing I recently installed insect nets on windows. It's quite impossible to stay still outdoors without repellent, they're relentless.
severe thunderstorm right at the MA-NY border. Maybe it'll reach us?
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. Cooling would seem to produce more favorable conditions for tornadoes in the U.S., but too much cooling would render it too cold for tornadoes to form. Perhaps the 1970's presented a favorable intensity of cooling? At any rate, there is a large amount of annual variation regardless of the general trend, and as we see in this so-far inactive season, it only takes one strong tornado to cause big-time destruction.
