Invercargill Big Freeze

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Invercargill Big Freeze

Unread post by Glenfelik »

Can anyone help me as to when the big Freeze was on in Invercargill in the 1990's?
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Re: Invercargill Big Freeze

Unread post by sthguy »

July 1996

An extreme cold period for the first 15 days of July resulted in all time low temperature records.
The average monthly temperature of 2.6 was the coldest ever recorded for any month in
Invercargill, and broke the previous record of 3.0 deg set in July 1995. Other records set were for
the lowest air temperature ever recorded and the most severe frost.

After a heavy snowfall over most of Southland on the 1st, a large anticyclone developed just to
the southeast of the South Island and became slow-moving. Skies cleared very quickly, and there
was little wind.

This allowed the already low temperatures to plummet further and over the next week and a half
the old record air and grass minimum temperatures for Invercargill were broken several times.
Despite long sunshine hours, daily highs were reluctant to go higher than 2 or 3 degrees and snow
lay unmelted for most of this time. Problems with transport and frozen water systems became
common throughout Southland.

As the anticyclone slowly drifted away, cloud gradually increased and temperatures rose a little,
allowing a thaw to set in after the 10th.
In the second half of the month, temperatures became milder than usual with much less frost.
Weather systems remained very slow-moving in the Tasman Sea - New Zealand area and this
prevented any further cold outbreaks occurring.


Now - let's not mention July 1996 without mentioning July 1995 :shock:

July 1995

July will be long remembered in the south for the persistence of cold wet weather, with
frequent snowfalls to low levels on the hills, bringing problems to many farmers, and icy
conditions which created hazardous driving conditions. Although snow was recorded on
10 days during the month in Invercargill ( a record for July ) it did not settle in any quantity
on low areas near the coast. However, many hill areas, especially in the east, had heavy

The direct cause of this spell of weather was a change in the circulation pattern in the
area south of Australia and the Tasman sea. A small area of high pressure persisted well
to the south of Tasmania, with an equally persistent area of low pressure to the south
and southeast of New Zealand. This combination directed a steady flow of very cold air
from near the Antartica coast, over the New Zealand area.

All air temperatures were well below normal. The average daily high, and the overall
mean monthly temperature were the coldest on record, eclipsing the previous lowest (
7.6 and 3.2 respectively ) which were recorded in 1968. The average overnight low of minus
1.1 degree fell just short of the record low ( -1.3 ) also in 1968.

This makes the month the coldest in Invercargill since records commenced.
Rainfall was 137% above normal and the highest recorded in July ( previous highs were July
1988 154mm, July 1974 135mm ).

Despite all this, sunshine was marginally above normal, the total was helped along by
two sunny days, recording 13 hours, at the end of the month
The average sea level pressure of 999hPa was also the lowest on record.

Highlights of the month included a period of hard frost from the 1st to the 4th, then wet
and stormy conditions from the 6th to the 10th with gales, snow, hail and thunderstorms
and the peak gust for the month of 61kts ( 113Kph).

There was a lull in the weather until the 16th, when another long very unsettled period
commenced and lasted until nearly the end of the month. This period of weather resulted
in large accumulations of snow in hill country areas in Eastern Southland and South
Climate is what you expect. Weather is what you get.