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hills and tornadoes

mid-April 1996, an F4 tornado kills half a dozen and stays on the ground for 30 miles of extremely rugged terrain in Stone and Izard Counties, Arkansas ... there is some video I've seen of the tornado literally blowing on top of and down 1,000-foot ridges ... I walked amid the ruins of homes flattened deep in river valleys between steep ridges ...
 
10-20 years ago i would buy the "theres no one out there to report one" but these days with all the outdoor enthusiasts and even storm chasers/spotters i dont buy it. I also wonder how different each of our ideas of what a mtn or hill is.
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I think your point is good: being originally from Denver, I note that my friends in Jacksonville FL consider a mountain any natural hill that allows you to see above the tree line (LOL); my standards are a touch more stringent ;).

As for the former comment, post-hoc storm analysis only takes place when damage is reported. Storms occuring over very hilly terrain do not register similarly to those on the Plains unless a Doppler radar station is nearby. No matter how many outdoorsmen (outdoorspeople?) there are, statistically there is still a lower probability of reporting in that area. My point wasn't that there isn't an increase in reporting in these areas (cell phones are now nearly ubiquitous even in areas I am shocked to find a signal), and so I concur that reporting in these areas is much improved. Still I would posit that the actual events that occur are more numerous than reports available.
 
I have a really good one:

Says its the highest elevation tornado in the US

Occured in the Sierra Nevada here in California:

http://tornado.sfsu.edu/RockwellPassTornado/index.html

Funnel.jpg
 
On June 2nd, I believe it was in 1999, a significant tornado hit Mt. Washington, a hilly bluff overlooking downtown Pittsburgh PA and the 3 Rivers.
It did significant damage to homes and trees in the area.
Photos of the storm revealed a stovepipe- type structure approaching the mountain from the West.
 
Here is something I have been curious about regarding this question:

Is it not possible for hills to aid tornado formation, by decreasing the distance between the thunderstorm base and ground level? It's common knowledge that many strongly rotating wall clouds and funnel clouds do not result in verifiable tornado touchdowns. I wouldn't be surprised if more than one of those would have been tornadoes if the ground below had been several hundred feet closer.
 
I've always wanted to see the aerial photos taken by Dr. Fujita's survey team of the tornadoes that crossed the high terrain of the West Virginia mountains on April 4, 1974 (the last few tornadoes of the Super Outbreak). Particularly the long-track tornado labeled 118 on this survey map:

wv1974.jpg


In addition to traversing rugged terrain at elevations ranging from 1,500 to over 3,000 feet, this tornado crossed one of the deepest sections of the the New River Gorge, around the Grandview-Prince area while producing F2 damage. The Gorge in this area drops around 900 feet from the ridges to the river. The entire terrain is heavily forested which should make damage patterns easy to spot.

Here is a shot of the terrain at Grandview:

http://chamorrobible.org/images/photos/gpw-20040705a.jpg

While we're on the subject, I've been trying to locate these Fujita damage survey photos, but all of my leads have run out - does anyone know where to find the images?
 
One of the May 31, 1985 tornadoes is a pretty good example of this too...

Although there were numerous other tornadoes that day across the lower lakes, probably the most intense tornado was the one that ripped across the Moshannon State Forest in Pennsylvania. This one cut a continuous 69 mile long, 2.2 mile wide path of F4 intensity through the ranges and deep forests of the Allegheny Mountains. If I remember correctly it was on the ground for about an hour and a half...

Nobody may have seen the tornado itself however, as it remarkably enough, stayed out to wilderness for nearly it's entire path. It obliterated about 85,000 trees, and even crossed the west branch of the Susquehenna River, twice! The aerial survey of the tornado (although I wasn't able to find any actual photos), showed that it virtually clear-cut the forest right to the ground, apparently. And, yes -- it even crossed some mountains that were in some cases up to 2000 feet high (I don't recall the exact names though).

Interestingly, the tornado ripped up so many trees that it was actually visible on radar, kind of like the Moore tornado of 1999 (quote from the Pittsburgh Post-Gazette):

"Even the meteorologists were transfixed. Greg Forbes, The Weather Channel's severe weather expert, was a professor of meteorology at Penn State in May 1985. On radar, he watched, riveted, as an F-4 tornado moved through Moshannon State Forest, across Clearfield, Clinton and Centre counties, sucking up so many trees that the debris could actually be seen on the screen as a little round ball in the center of a hook-shaped radar "echo" -- the mark of a tornado. Using the reverse terminology peculiar to meteorologists, Forbes described it "as one of the best radar signatures I've ever seen."

A couple of links --
http://www.angelfire.com/pa/pawx/053185.html
http://www.post-gazette.com/pg/05149/511826.stm


Eric
 
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