Rakaia Tornado - " A week Ago"

NZ Thunderstorm Soc · Thu 19/08/2004 18:49

According to yesterday's Christchurch Star a week ago, a couple from Christchurch were returning back from Geraldine when they spotted a 'mini' tornado just south of Rakaia.
They took some photos one which was published in the paper on page 3
Judging back to my records, that was the day when a SW squall struck CHcH about 10am?
does anyone else have any informatiopn on this?

JohnGaul
NZTS

03Stormchaser · Unread post by **03Stormchaser** » Thu 19/08/2004 20:45

What day did they say it was?

NZ Thunderstorm Soc · Thu 19/08/2004 21:07

03 Stormchaser wrote:What day did they say it was?

they didn't.
all was said in the article was the ChCh couple were on their way back home from Geraldine, a week ago, so that would make the date the 11th of August which was the day the southerly squall came through ChCh around 10am.

The article was entitled
"Local Twister Provokes Curiousity"
The ChCh Star is not online but maybe Jeff Northcote may be able to source the article from yesteray's Star!

Eh Jeff

JohnGaul
NZTS

Thunder · Unread post by **Thunder** » Thu 19/08/2004 23:50

Thanks John, I grabbed the copy of the star from yesterday and see the tornado. Lucky no one had used it for the fire! (the paper that is)

So this was the day when I said I saw the awsome looking front going across the Canterbury Plains? This day:

http://www.weatherforum.org.nz/forum/vi ... 0&start=15

Ah yes, it was as I saw my post date relates to then. There wasn't much if any lightning from that front as I recall but it did look awsome. Another tornado to add to the records.

I'll see if I can put up a scan of it tomorrow for others to see, the photo is pretty small and doesn't show much but you can see it.

NZstorm · Unread post by **NZstorm** » Fri 20/08/2004 06:40

just looking back at temperatures,

prefrontal about 6C,

After front about 4C,

So funnel developed in very cold conditions. I have never heard of a funnel over land in such cool weather. It must have formed on the frontal wind change. I look forward to seeing the photo.

jeffsweather · Unread post by **jeffsweather** » Fri 20/08/2004 08:39

NZ Thunderstorm Soc wrote: The article was entitled
"Local Twister Provokes Curiousity"
The ChCh Star is not online but maybe Jeff Northcote may be able to source the article from yesteray's Star!

Eh Jeff

OK John, I didn't see the Star last night but I'll have a look through tonight and put it on my web site. I'll post here when its available.

Thunder · Unread post by **Thunder** » Fri 20/08/2004 13:34

Here's that pic, maybe Jeff can do a better scan as I feel I haven't done something right. The picture to begin with isn't that great but here it is:

It travels from the upper right hand corner down towards the lower left hand corner.

Maybe it was a wide angle shot and the Christchurch Star cropped just that tornado part out of the photo. Maybe that's why it's low in quality?

The blurred trees in the foreground are the result of them traveling in their car and taking the photo.

Gary Roberts · Unread post by **Gary Roberts** » Fri 20/08/2004 13:51

Aaron J Wilkinson wrote:Here's that pic...

Looks like smoke from a chimney to me!

Thunder · Unread post by **Thunder** » Fri 20/08/2004 15:13

Yeah I know what you mean Gary

But, the artical says how the people who took the photo saw it grow in length, I guess smoke from a chimney could for that matter aswell but it just looks more like a tornado to me than chimney smoke. Maybe it's chimney smoke being caught in a twirling updraft?:D:-k

It has that nice grace a tornado has to it, where as smoke coming out of a chimney is all ruggedy looking.

NZstorm · Unread post by **NZstorm** » Fri 20/08/2004 16:44

Yes, I agree with Gary. Its a lousy picture of smoke.

Thunder · Unread post by **Thunder** » Fri 20/08/2004 17:12

Ah, your probably right. John, can you rescue my enthusiam?

This is what the artical said anyway:

Local twister provokes curiosity

Karen and Andrew Pound couldn't believe their eyes when they spotted a tornado just south of Rakaia.
"We saw this thing on our left," Karen said. "Andrew said 'there's a tornado' and it actually was. We were watching it grow longer and longer."
The Christchurch couple were on their way back from a day trip to Geraldine a week ago.
Andrew urged Karen to dig out here digital camera, and she hung out of the car window, snapping away.
Methven Constable Don Eggleston knew nothing of the tornado, and said no damage had been reported.

It is going up into a cloud, the photo from the star is a bit clearer, whether it's a tornado or not, I'm not sure? John???!!

NZ Thunderstorm Soc · Fri 20/08/2004 18:21

...sorry lads, judging by the photo that Aaron put up (which is much clearer than the photo in the newspaper) it does look like smoke ...
...but I think it isn't.

I think it is what I call a "Vaccum Hose Vortex"
That is a very thin,vaccum cleaner hose size form of vortex extending from the cloud in very cold turbulent conditions.
It appears to looks like smoke from a fire but then again it dosen't as it is very frail around the edges.
Wind speeds inside can get up to either calm or just of calm when a photograph of it can be taken.
As it is cold it is very weak and lasts long enough for someone to take a photo of it and send to a local newspaper

JohnGaul
NZTS

tich · Unread post by **tich** » Fri 20/08/2004 18:49

Judging back to my records, that was the day when a SW squall struck CHcH about 10am?

Yes a cold wet southerly blast (virtually nothing compared to what happened more recently) hit Chch, but I don't recall any thunder or hail activity, the sort of weather that can spawn tornadoes.

NZ Thunderstorm Soc · Fri 20/08/2004 19:16

tich wrote:
Judging back to my records, that was the day when a SW squall struck CHcH about 10am?
Yes a cold wet southerly blast (virtually nothing compared to what happened more recently) hit Chch, but I don't recall any thunder or hail activity, the sort of weather that can spawn tornadoes.

Yes, Ben,
I might write a letter to the editor of the ChCh Star regarding that item.

JohnGaul
NZTS

jeffsweather · Unread post by **jeffsweather** » Fri 20/08/2004 19:20

Aaron J Wilkinson wrote:Here's that pic, maybe Jeff can do a better scan as I feel I haven't done something right. The picture to begin with isn't that great but here it is:

I scanned the story but can't get the picture much better then Aaron. Even looking at the photo on the paper, it's really low contrast. Anyway, it was best in greyscale but still not very clear. It also didn't help that the paper got wet in the mail box

Have a look here
http://weather.northcott.co.nz/news/rakaia_tornado.php

03Stormchaser · Unread post by **03Stormchaser** » Fri 20/08/2004 19:24

Also to note NIWA senior climate scientist Jim Salinger said New Zealand
had 20-30 tornadoes a year. These were 10-30 meteres lang and ran along a 1km to 5km path.

Salinger said the longest tornado path recorded was 16km in Taranaki.

The tornado season here is from May to september, predominantly in the Taranaki, Bay of Plenty and Auckland regions, he said.

I beg to differ the season here is more like Augest to December with the exception to the West Coast and Taranaki which I believe could get tornadoes at anytime of the year. Most of these on the Coast would not be recorded. Due to the low population.

NZstorm · Unread post by **NZstorm** » Fri 20/08/2004 19:48

The tornado season here is from May to september, predominantly in the Taranaki, Bay of Plenty and Auckland regions, he said.

I think I would add the SI West Coast and Waikato to that list.

Thunder · Unread post by **Thunder** » Fri 20/08/2004 21:39

And add Gore due to the FC there last year on the 24th Dec 03

That scan Jeff brings it out more, I haven't seen smoke coming out of a chimney like that. It'll be something along the lines of what John's talking about. Maybe if you email them John you could request the full sized pic as I reckon that one was cropped. It was taken with a digital camera as the story suggests so you should be able to obtain it, provided the Star let you. There's some twisting motions involved there I believe.

jeffsweather · Unread post by **jeffsweather** » Sat 21/08/2004 09:12

Aaron J Wilkinson wrote: That scan Jeff brings it out more, I haven't seen smoke coming out of a chimney like that.

Not much contrast in the printed photo, even looking at the photo, it's very difficult to see any fine detail, just the funnel is lighter than the background colour. It doesn't look like smoke.

Manukau heads obs · Sat 21/08/2004 14:49

i agree!
not a tornado
reasons:
it they were going back to CHCH, and it was on there left (i.e thats the southern alps behind), then that also looks like the trailing edge of the frontal cloud....but tornadoes for at the leading edge, where the actual frontal boundary is...
also, tornadoes where they meet the ground are more straight up and down...not still leaning over
also, there are small "bumps" along the edge...like you would get with smoke...
also, they way they describe it getting longer, makes it sound like extending more and more to the right....like smoke would (or eaxtly like john gaul says)

03Stormchaser · Unread post by **03Stormchaser** » Sun 22/08/2004 08:43

Manukau heads observer wrote:i agree!
not a tornado
reasons:
it they were going back to CHCH, and it was on there left (i.e thats the southern alps behind), then that also looks like the trailing edge of the frontal cloud....but tornadoes for at the leading edge, where the actual frontal boundary is...
also, tornadoes where they meet the ground are more straight up and down...not still leaning over
also, there are small "bumps" along the edge...like you would get with smoke...
also, they way they describe it getting longer, makes it sound like extending more and more to the right....like smoke would (or eaxtly like john gaul says)

Im still adament that it is a tornado. I have emailed the Christchurch Star too see if its possible to get a copy of the orignals. Remember there was more than one photo taken. Also the scan does not do it justice, because it is scanned off Newsprint

NZ Thunderstorm Soc · Sun 22/08/2004 12:47

03 Stormchaser wrote: I have emailed the Christchurch Star too see if its possible to get a copy of the orignals. Remember there was more than one photo taken. Also the scan does not do it justice, because it is scanned off Newsprint

I couldn't find an email for the ChChSTAR

I suppose they have one ??

JohnGaul
NZTS

NZstorm · Unread post by **NZstorm** » Mon 23/08/2004 18:32

The problem I have with the Rakaia Tornado is that the day was a cold dry stable day. The only bit of moisture was on a very weak cold front which passed through about 10am. But conditions in this front were quite stable as Aaron's photos will confirm. Morning dewpoints at CH Airport were around 2C or 3C, falling to -3C in the late afternoon.

The time this reported tornado occured would be interesting. Was it am or pm.

If there is no confirmed report of a funnel touching the ground, the occurance is reported as a funnel cloud, not a tornado.