Hurricane winds vs Tornadic winds

[Mike Hollingshead]

Any thoughts on which would have more 'force' in the area it's in...a 150 mph tornadic wind or a 150 mph hurricane wind, or would there be a difference? I would think the tornadic wind would have more of an impact because of how much 'torque' that can be involved. Then again a cane's wind might be more persistant. I think the rapid change in direction has a greater impact with tornadoes. Canes also seem to build up a gust more then a tornado would. A tornado you can sort of go from very little to bam.... Just something that I just wondered about.

 

[Charles Allison]

I have wondered the same thing. I would think the tornadic winds of 150 mph would have to be way more destructive because people think it is ok to drive into these hurricane situations but if someone were to talk about driving into a tornado with winds even less (F0 40-72mph or F1 73-112mph) they are considered insane, gonna get someone killed, give chasers a bad name etc.

 

[Jeff Snyder]

I have wondered the same thing. I would think the tornadic winds of 150 mph would have to be way more destructive because people think it is ok to drive into these hurricane situations but if someone were to talk about driving into a tornado with winds even less (F0 40-72mph or F1 73-112mph) they are considered insane, gonna get someone killed, give chasers a bad name etc.

The difference in perception is interesting, isn't it? People complain how driving into a tornado (the VAST majority of which are weak, small, and short-lived) is stupid or gives chasers a bad name, yet nobody really 2nd-guesses chasing hurricanes. I for one don't have a problem with either.

The only reason why I'd think the tornadic winds would be any worse would be because the winds tend to change directions much more rapidly with tornadoes (smaller size, etc). In addition, there's more significant vertical velocities with tornadoes, though I suppose the near-ground vertical velocity for either is small or non-existant (practically, not scientifically). Then again, the sustained nature of strong hurricane winds can really do signfiacnt damage as well...

 

[Glen Romine]

The best known survey of hurricane damage that I'm aware of was from Hurricane Andrew, which had swaths of F-3 equivalent damage - and this is from a high end CAT 4 to maybe CAT 5 intensity storm - so around 150 mph estimated peak sustained winds - yet the Fujita scale suggests winds slightly higher than this are needed for F3 damage, so perhaps gusts exceeded 160 mph, or it could have been the cumulative effect of continued exposure. I'm not really aware of any other post-storm survey that even comes close to the level of detail from that one - but you'd probably want to look at a few before making any generalizations.

Glen

 

[Jeff Wear]

I don't know if you can compare what a hurricane chaser does to what the people who want to drive into a tornado does....a hurricane chaser is usually not driving around during the strongest winds - they are usually taking shelter in a parking garage or sturdy structure.

Also another thing to consider about tornadoes is when the wind from the tornado is hitting you, there's usually nothing to buffer you or whatever structure you're in from the full effects of the wind. At least with a hurricane or straight line wind trees and buildings or even slight variations in terrain can provide somewhat of a buffer from the wind (assuming you're not out in the open).

It should be noted though that winds rarely get much higher than 120 mph on land during a hurricane - Camille and Andrew were perhaps two of the only hurricanes in the mainland US the past 50 years that produced 150 mph winds on land.

 

[B Ozanne]

Another thing to consider is that observers of hurricanes rarely experience the advertised wind speed while tornadoes easily meet and exceed of the estimated wind speeds.

 

[Jeff Snyder]

Another thing to consider is that observers of hurricanes rarely experience the advertised wind speed while tornadoes easily meet and exceed of the estimated wind speeds.

Well I don't know about this... The "advertised" winds in hurricanes likely occur on a very local scale, same as with tornadoes. I've never heard of a problem over "underestimating" tornadic wind speeds...

 

[Bridget Beddow]

You know something else that gets me,

Looking at it from a weather-uneducated point of view,being me.

We've talked consistently in here about how the upper level winds of the hurricane are much faster than the lower level (close to the ground) due to topography/man-made obstructions, and how it has an effect on the wind speed and why you don't feel the sustained winds as much as you would on top of a 5-story building.

However, when talking about tornadoes, consistantly I have read (from many sources) how topography does not affect the tornadoes and their wind-speed or direction.

Isn't it strange how topography lends so much to how a hurricane works and yet does not affect tornadoes in the same respects?

 

[rdale]

It's not just topography as much as it is friction... Winds 50ft up in a tornado are much stronger than at the surface, which is why doppler radar wind estimates are not considered ground truth.

And another clarification: "yet the Fujita scale suggests winds slightly higher than this are needed for F3 damage"

The Fujita scale is not a wind speed scale, it is a damage scale.

- Rob

 

[Glen Romine]

And another clarification: "yet the Fujita scale suggests winds slightly higher than this are needed for F3 damage"

The Fujita scale is not a wind speed scale, it is a damage scale.

- Rob

Thanks Captain, but you miss the context in how it is used here. In this case - we have damage, caused by a hurricane, and that damage is consistent with F3. Our wind speed that was believed to have caused that damage is less than that suggested by the Fujita scale - so there is an inconsistency. I then offered some speculation for why these might be inconsistent (exposure time or gusts). While it is true that the Fujita scale is a damage scale - the very purpose for its existance was as a first order approximation of the wind speeds needed to cause that level of damage so that a climatology could be built to determine the rarity of extreme wind events.

Glen

 

[rdale]

"Our wind speed that was believed to have caused that damage is less than that suggested by the Fujita scale - so there is an inconsistency."

No, because all scientific research into the winds associated with F-scale shows that the F-scale winds are too high... The hurricane info only adds to that conclusion.

"the very purpose for its existance was as a first order approximation of the wind speeds needed to cause that level of damage"

But since the wind speeds were not determined scientifically, that should indicate that the particular wind speeds should not be used scientifically. The damage scale is "accurate" which adds to the value of F-scale, not F-winds.

-Rob

 

[Glen Romine]

No, because all scientific research into the winds associated with F-scale shows that the F-scale winds are too high... The hurricane info only adds to that conclusion.

-Rob

But you are missing the point of this thread - here we are comparing tornadic winds to hurricane winds and are trying to establish if one is more or less likely to cause greater damage for the same wind speed. It doesn't matter if there is a bias.

Glen

 

[Bridget Beddow]

But you are missing the point of this thread - here we are comparing tornadic winds to hurricane winds and are trying to establish if one is more or less likely to cause greater damage for the same wind speed. It doesn't matter if there is a bias.

If that's the case, then isn't it reasonable to assume that since friction (it seems) has less of an effect on tornadoes (maybe b/c of the concentration of the force?) at ground levels...(the same force being deterrable by obstructions in a hurricane) that a tornado will do much more damage since relative to it's size it has fewer obstructions than a hurricane?

Or, let's say if you could get a tornado to last the same amount of time as a hurricane-could it do more damage than a hurricane since the obstructions provide a "counter-productive" measure to the hurricane wind speeds?

How would you even begin comparing the two since size counts for one thing, topography/land mass counts for another (since it takes an ocean to fuel a hurricane)

 

[Glen Romine]

Bridget,

The effects of friction are common to both tornadoes and hurricanes - however the force balances driving both circulations are not the same based on differences in scale. The size of the "obstructions" for the tornado are actually probably more damaging to that circulation than to a hurricane, at least on short time scales. The width of peak damage is very small portion of both the tornado and hurricane damage swath, but the much larger hurricane circulation has a proportionally wider swath.

Glen

 

[Bridget Beddow]

Bridget,

The effects of friction are common to both tornadoes and hurricanes - however the force balances driving both circulations are not the same based on differences in scale. The size of the "obstructions" for the tornado are actually probably more damaging to that circulation than to a hurricane, at least on short time scales. The width of peak damage is very small portion of both the tornado and hurricane damage swath, but the much larger hurricane circulation has a proportionally wider swath.

Glen

Okay, this is mind-boggling-to me anyway.

I would be much more afraid of driving into a tornado, because the concentration and updraft allow for too many items that get caught up and become killing objects. Objects in a hurricane do not get caught in an updraft in as much of an isolated condition as tornadoes, and do not sustain as much force since they are not carried as a tornado will carry an object - there's not enough updraft force and fall back to the ground quicker in a hurricane (is what I'm thinking). But I also don't remember seeing things like a 2 inch piece of wood being driven into a wall from a hurricane, not to say it hasn't happened.

It's also alot easier to see a flying object in a hurricane, if you're in a good spot for viewing, which is easier to pick out before a hurricane than it is a tornado since you have a longer period of time to prepare before a hurricane hits.

But, also, I am at the "bottom of the food chain" when it comes to meteorology and also could be considered like the "general public" who has these viewpoints because of the media and what is picked out by the media to be shown on television. I've also been through many more hurricanes than I have tornadoes and have not experienced quite the damage that is generally shown on television, but I have seen quite a bit more damage from tornadoes and therefore can consider my viewpoints on hurricanes and tornadoes as a bias point of view, simply b/c of past experience.