NZ Weather Forum

I've been downloading wind gust data from the national climate database for a number of sites, and the highest gust I have found so far is 203.8kmh (110knots)at Manukau Heads on 21 Feb 1992. I've also found Baring Head had a 200kmh (108knots) gust. Christchurch has had 172.4kmh (93 knots) on 1 Aug 1975 - was this 'The Big Blow' where gusts on the Kaikoura peninsula reached 194kmh (105knots)?

The most consistently windy place I've found so far is Mt Kaukau which has an average daily max gust of 82.0kmh (44knots).

According to an old weather Calender the quoted record is 248kmh (134knots) at Hawkins Hill near Wellington and 250kmh (135knots) at Mt John in Canterbury on 18 April 1970. 'The New Zealand Weather Book' by Erick Brenstrum quotes 181kmh (98knots) gusting 269kmh (145knots) at Oteranga Bay in Wellington during Giselle. I don't know where I read it but I read something about a severe storm which produced 275kmh (149knots) in Wellington some time ago but I can't find this info.

David wrote:I've been downloading wind gust data from the national climate database for a number of sites, and the highest gust I have found so far is 203.8kmh (110knots)at Manukau Heads on 21 Feb 1992. I've also found Baring Head had a 200kmh (108knots) gust. Christchurch has had 172.4kmh (93 knots) on 1 Aug 1975 - was this 'The Big Blow' where gusts on the Kaikoura peninsula reached 194kmh (105knots)?

The most consistently windy place I've found so far is Mt Kaukau which has an average daily max gust of 82.0kmh (44knots).

According to an old weather Calender the quoted record is 248kmh (134knots) at Hawkins Hill near Wellington and 250kmh (135knots) at Mt John in Canterbury on 18 April 1970. 'The New Zealand Weather Book' by Erick Brenstrum quotes 181kmh (98knots) gusting 269kmh (145knots) at Oteranga Bay in Wellington during Giselle. I don't know where I read it but I read something about a severe storm which produced 275kmh (149knots) in Wellington some time ago but I can't find this info.

For straight windrun, I think SW Cape on Stewart Island is the top one I've seen, with a mean run of about 900km/day (ie 37.5kph average). The Oteranga Bay figure is quite believeable but not officially accepted as there was some doubt about the state of the instrument. I've never seen a quote anywhere about a 275kph gust anywhere in W'gton, sure that isn't correct. The highest daily windrun I've seen was at Baring Head during one of the Feb 2004 storms - about 2725km, meaning an average speed of about 113 kph.

I can recall someone presenting a paper about windiness at mountain elevations - estimating among other things that the gale that blew a hut off Mt Cook in Jan 1977 may have gusted to well over 320kph, from rather vague memory.

What about the windspeed data from Cyclone Bola? I know winds reached just over 200kmh through cook strait.
But were there other stations on higher ground that could have recorded higher gusts?.
Cheers
Jason.

RWood wrote:I've never seen a quote anywhere about a 275kph gust anywhere in W'gton, sure that isn't correct.

http://homepages.ihug.co.nz/~glaive/nz/ ... yclone.htm
Here's one site i just found where the 275kph figure is present - apparently in the Giselle storm.

I can believe SW cape is the windiest place - being closer to the roaring 40's and the polar storms south of NZ than any other part of the country. Cape Reinga can cop some pretty tremendous winds from cyclones occasionally.

But one thing I wonder is how can Manukau Heads have a high gust of 204kmh in the recording history but Auckland Aero only has a highest gust of 146kmh?

That 275kph value will just be a slight misquotation of the Oteranga Bay figure, I'm confident of that.

Jasestrm wrote:But were there other stations on higher ground that could have recorded higher gusts?

Manukau heads in Auckland got 150km/h on 10 March 1988, which is a higher area of Auckland, Whangarei Aero had 124km/h, Kaitaia had 121kmh.

Strangely enough Castlepoint only had a peak gust of 85km/h and Wellington Aero 115km/h. Gisborne area was hard hit (mainly by floods) but records have a peak gust of 93kmh. Some areas had 1000mm rain over 4 days. The NZ weather book covers the great storm of 36, bola and giselle but wind speeds are only mentioned for Gisele unfortunately. I've tried many stations to find data on Bola on the climate database but data ends around 1985-1986 for many sites, and there were not very many established recording stations in the time of Gisele either.

If the SW regime like today was here all the time Auckland would rank as one of the windiest places in N.Z

What do you guys think of the Beaufort scale? I think the speeds are too low for their category and the damage they cause is over-estimated. I mean, who would call 80km/h gusts a strong gale and 90km/h gusts storm force? Really 90km/h is only enough to break twigs and small branches (with a few exceptions), not enough for "Seldom experienced inland; trees uprooted; considerable structural damage" in this page: http://www.bom.gov.au/lam/glossary/beaufort.shtml.
I would revise the scale to something like this:
Gale.............gusts of 70-90km/h
Strong gale.....gusts of 90-110km/h
Storm...........gusts of 110-130km/h
Violent Storm..gusts of 130-150km/h
Hurricane.......gusts of 150km/h+

If I am wrong and the Beaufort scale describes damage in terms of average wind speed and not the gusts, someone correct me?

Rwood, the Manukau Heads signal station is at the extreme northern tip of the south head of the entrance to the Manukau harbour, at 888 feet high with a very steep slope (45o) to the water below, and the entrance to the harbour is relatively narrow and the waitakere ranges on the other side are also very steep and rise to over 1000 feet
and so its a real wind funnel in West and NE winds
(in westerly winds, the wind will average 55 knots there easily, when only 25 to 30 knots on the harbour

Jeez , I can't imagine many trees would be growing on the Manukau heads signal station area, and, 200Kmph!!

Manukau heads observer wrote:(in westerly winds, the wind will average 55 knots there easily, when only 25 to 30 knots on the harbour

many of the severe gusts in the data set (daily maximum wind gusts with direction to the nearest 10degrees) for Manukau Heads occured between the directions 300 degrees to 360 degrees. So I was thinking NW must funnel through?

You should push for NIWA or someone to set up a windrun measurement at Manukau Heads (as well as gust speeds) - I'm keen to see some place surpass SW Cape (the latter is at sea level so its numbers are quite impressive).

Westerlies can be gusty here like today,not continual leaf shaking but not extreme like SW and NW arnt too bad here in Manurewa and NE not too bad though can get strong when the front gets close,all other directions arnt too windy though SSW can be gusty.

Requoted cannot delete?

I'm picking either Wellington or Invercargill will be our windiest main City and Auckland or Whangarei to be the least windy.

spwill wrote:Auckland or Whangarei to be the least windy.

Are you kidding? Surely Auckland is far windier than places like Christchurch, Hamilton, Rotorua, Taupo, etc.
Auckland is exposed to the west and these places are not as exposed.

David wrote:

spwill wrote:Auckland or Whangarei to be the least windy.

Are you kidding? Surely Auckland is far windier than places like Christchurch, Hamilton, Rotorua, Taupo, etc.
Auckland is exposed to the west and these places are not as exposed.

If that theory was correct then Westport, Greymouth and Hokitika would be equally windy???

spwill wrote:I'm picking either Wellington or Invercargill will be our windiest main City and Auckland or Whangarei to be the least windy.

Of the "cities", Whangarei,Rotorua, Taupo, Hamilton, Gisborne, Napier, Hastings, Masterton, Nelson, Christchurch and Dunedin would all be less windy than Auckland. I can't find (!!!) (offhand) a table of the top 15-20 urban areas by population, or I might think of a better list.

Westport, Greymouth and Hokitika have their windspeeds modified by an alpine barrier effect. The only significant centres that I would pick to be clearly windier than Auckland would be New Plymouth, Palmerston North, (possibly) Wanganui, Wellington and Invercargill.

David wrote:What do you guys think of the Beaufort scale? I think the speeds are too low for their category and the damage they cause is over-estimated. I mean, who would call 80km/h gusts a strong gale and 90km/h gusts storm force? Really 90km/h is only enough to break twigs and small branches (with a few exceptions), not enough for "Seldom experienced inland; trees uprooted; considerable structural damage" in this page: http://www.bom.gov.au/lam/glossary/beaufort.shtml.
I would revise the scale to something like this:
Gale.............gusts of 70-90km/h
Strong gale.....gusts of 90-110km/h
Storm...........gusts of 110-130km/h
Violent Storm..gusts of 130-150km/h
Hurricane.......gusts of 150km/h+

If I am wrong and the Beaufort scale describes damage in terms of average wind speed and not the gusts, someone correct me?

You are wrong. The Beaufort scale does indeed describe effects in terms of average wind speed.

Manukau heads observer wrote:Rwood, the Manukau Heads signal station is at the extreme northern tip of the south head of the entrance to the Manukau harbour, at 888 feet high with a very steep slope (45o) to the water below, and the entrance to the harbour is relatively narrow and the waitakere ranges on the other side are also very steep and rise to over 1000 feet
and so its a real wind funnel in West and NE winds
(in westerly winds, the wind will average 55 knots there easily, when only 25 to 30 knots on the harbour

It was David who was wondering why the Heads had such a high speed record...

RWood wrote:

spwill wrote:I'm picking either Wellington or Invercargill will be our windiest main City and Auckland or Whangarei to be the least windy.

Of the "cities", Whangarei,Rotorua, Taupo, Hamilton, Gisborne, Napier, Hastings, Masterton, Nelson, Christchurch and Dunedin would all be less windy than Auckland. I can't find (!!!) (offhand) a table of the top 15-20 urban areas by population, or I might think of a better list.

It all depends on how you define "windiest"? Common ways to do so include total annual wind run, which is a measure of long term average windiness; highest wind gust (which is a very short term measure of an extreme); or number of days when the wind reaches a certain criteria (commonly either gusts to a certain level, or mean speeds to a certain level, often gale force).

I had in mind average windruns, picking in each case a typically open area like an airport. Given those criteria, I think my lists would pass muster.

David wrote:What do you guys think of the Beaufort scale? I think the speeds are too low for their category and the damage they cause is over-estimated. I mean, who would call 80km/h gusts a strong gale and 90km/h gusts storm force? Really 90km/h is only enough to break twigs and small branches (with a few exceptions), not enough for "Seldom experienced inland; trees uprooted; considerable structural damage" in this page: http://www.bom.gov.au/lam/glossary/beaufort.shtml.
I would revise the scale to something like this:
Gale.............gusts of 70-90km/h
Strong gale.....gusts of 90-110km/h
Storm...........gusts of 110-130km/h
Violent Storm..gusts of 130-150km/h
Hurricane.......gusts of 150km/h+

If I am wrong and the Beaufort scale describes damage in terms of average wind speed and not the gusts, someone correct me?

Those speeds dont categorise properly because it depends on what trees you are referring to, as alot of deciduous trees such as Willows,Poplars,Oak's etc are much weaker and would break off small branches in 50-60kmh winds.
Evergreens would be much stronger, such as our natives.
40-50kmh I would consider strong winds
60-100kmh Gale force winds
100-130kmh severe gale
130kmh+ Hurricane force.
Is the correct term I believe and always has been, and I am sure if you read windcharts from MS etc you will see what I mean.
Cheers
Jason.

Are you kidding? Surely Auckland is far windier than places like Christchurch, Hamilton, Rotorua, Taupo, etc.
Auckland is exposed to the west and these places are not as exposed.

The Westerlies tend to be stronger east of high ground.

Of the "cities", Whangarei,Rotorua, Taupo, Hamilton, Gisborne, Napier, Hastings, Masterton, Nelson, Christchurch and Dunedin would all be less windy than Auckland.

The eastern locations have more strong wind events , thats what I mean by windy.
Wind run takes into account light to fresh wind, calm days in Auckland are rare