Climate Summary for Winter 2006 Winter 2006: Wild in the lower North Island, exceptional snowstorms in the east of the South Island, but quite benign in the north of both islands. New high sunshine records in places. ·          Rainfall: Wet in the southern half of the North Island, especially Wanganui, Wairarapa, and Wellington; relatively dry in the north of both islands, and Otago ·          Temperature: Below normal in the north and west of the North Island, Buller, South Canterbury and east Otago; near normal elsewhere ·          Sunshine: Extremely sunny for winter with record winter sunshine in parts of the north and west of the North Island and the southeast of the South Island This was a winter of extremes in parts of New Zealand, with exceptional snowstorms in the east of the South Island, significant snowfall also in the central North Island, severe floods and landslips in the lower North Island, and damaging winds. In contrast it was also very sunny in many areas and dry in the north of both islands and Otago. Winter rainfall was at least 150 percent (one and a half) of normal in Wanganui and Wairarapa, and parts of Wellington (including Kapiti). Soil moisture in these regions was already at field capacity (nearly saturated) at the start of June. In contrast, winter rainfall was only about 50 percent (half) of normal in parts of Northland and Otago, and below normal in Thames-Coromandel, Western Bay of Plenty, much of Auckland, Nelson, and much of Marlborough. The national average winter temperature of 8.1°C was close to normal, being 0.2°C below average. This was lowest since 1997, as many recent winters have been much warmer than normal. Seasonal mean temperatures were below normal throughout much of the north and west of the North Island from Northland to Horowhenua, as well as Buller, South Canterbury and Otago, but near normal elsewhere. This winter was also unusual because June was an exceptionally cold month, the coldest month of the winter. Temperatures, for New Zealand as a whole, were above or near normal for the remainder of winter. Sunshine hours for winter were extremely high in the north and west of the North Island from Northland to Wellington, and in the east of the South Island from inland South Canterbury to Southland, with some centres recording their sunniest winter on record. The overall winter climate pattern was dominated by more frequent anticyclones ('highs') than usual in the Australian Bight, often extending into Tasman Sea. This pattern produced frequent southerly winds over the North Island and southwesterlies over southern New Zealand.

Climate Summary for Winter 2006 

Winter 2006: Wild in the lower North Island, exceptional snowstorms in the east of the South Island, but quite benign in the north of both islands. New high sunshine records in places.

·          Rainfall: Wet in the southern half of the North Island, especially Wanganui, Wairarapa, and Wellington; relatively dry in the north of both islands, and Otago

·          Temperature: Below normal in the north and west of the North Island, Buller, South Canterbury and east Otago; near normal elsewhere

·          Sunshine: Extremely sunny for winter with record winter sunshine in parts of the north and west of the North Island and the southeast of the South Island

This was a winter of extremes in parts of New Zealand, with exceptional snowstorms in the east of the South Island, significant snowfall also in the central North Island, severe floods and landslips in the lower North Island, and damaging winds. In contrast it was also very sunny in many areas and dry in the north of both islands and Otago.

Winter rainfall was at least 150 percent (one and a half) of normal in Wanganui and Wairarapa, and parts of Wellington (including Kapiti). Soil moisture in these regions was already at field capacity (nearly saturated) at the start of June. In contrast, winter rainfall was only about 50 percent (half) of normal in parts of Northland and Otago, and below normal in Thames-Coromandel, Western Bay of Plenty, much of Auckland, Nelson, and much of Marlborough. The national average winter temperature of 8.1°C was close to normal, being 0.2°C below average. This was lowest since 1997, as many recent winters have been much warmer than normal. Seasonal mean temperatures were below normal throughout much of the north and west of the North Island from Northland to Horowhenua, as well as Buller, South Canterbury and Otago, but near normal elsewhere. This winter was also unusual because June was an exceptionally cold month, the coldest month of the winter. Temperatures, for New Zealand as a whole, were above or near normal for the remainder of winter. Sunshine hours for winter were extremely high in the north and west of the North Island from Northland to Wellington, and in the east of the South Island from inland South Canterbury to Southland, with some centres recording their sunniest winter on record. The overall winter climate pattern was dominated by more frequent anticyclones ('highs') than usual in the Australian Bight, often extending into Tasman Sea. This pattern produced frequent southerly winds over the North Island and southwesterlies over southern New Zealand.

Major Highlights

·          The highest temperature recorded during the winter was 21.8°C recorded at Timaru Airport on 29 August. The lowest air temperatures for the winter were -14.0°C recorded Tara Hills, Omarama on 14 June and Fairlie on 28 June. The minimum air temperatures were -10°C or lower in parts in inland South Canterbury and/or North Otago, on nine days between 14 and 29 June.

·          High rainfall events were frequent throughout the winter, occurring on at least eight occasions; the worst event occurring over 4-6 July in the Wairarapa, Wanganui and Wellington regions. Over 300 mm was reported within 24 hours in parts of South Wairarapa, where people had to be evacuated from their homes. Martinborough was isolated by floodwaters, and surface flooding which also affected Greytown and Carterton. In Wairarapa, more than 50 roads were closed due to flooding or landslips. The settlement of Mangamahu (northeast of Wanganui) was isolated by the collapse of the Mangawhero river bridge. A house in Wanganui was struck by a landslide, with two others later affected in Hunterville.

·          The highest wind gust for the winter was 167 km/h from the northwest was recorded at Southwest Cape (Stewart Island) on 28 August. A tornado damaged property in Greymouth on 11 June, and also destroyed property in the Waikato on the 12 July. Northwest gales buffeted the North Island on 12 June, with damage and power outages in parts of Auckland, Thames-Coromandel, Waikato, and the Marlborough Sounds. Trees fell in Tauranga, with other wind damage in Kaitoke and Nelson. Power lines were damaged by wind in Taranaki, Bay of Plenty, and Gisborne, on 19 June, with power cut to thousands of residents. Several iron roofs were damaged in Gisborne, and New Plymouth.

The worst of the winter snowfall events occurred in Canterbury over the night of 11/12 June, especially in the south, snow settling to depths of 75-90cm around Fairlie and Burkes Pass, almost 40cm in Ashburton, and more than 20cm in Timaru, some remaining in some inland areas until the 27th. Extended power cuts occurred throughout much of South Canterbury, due to broken power lines and poles. The roofs of several buildings also collapsed, due to the weight of snow. Many motorists were stranded in the snow, and many roads closed. Southerlies spread over the North Island over 20-22 June, bringing heavy snowfall down to 500m, affecting the Desert Road, and townships of Waiouru, Ohakune, National Park, and the outskirts of Taupo, with many roads closed, including those to the east coast. Two buses slid off icy roads in the Central North Island, and nearly 100 cars were stranded in the snow.

Of the five main centres, Wellington was the wettest, Dunedin easily the driest and Auckland the sunniest. Rainfall was above average in Wellington and Christchurch, below average in Auckland and Dunedin, and near average in the other main centres. Temperatures were near average in Wellington, but below average in the four other main centres. Winter sunshine hours were above average in all five cities, with Dunedin recording its sunniest winter on record.

Rainfall

Winter rainfall was at least 150 percent (one and a half) of normal in Wanganui and Wairarapa, and parts of Wellington (includes Kapiti), and also above normal in Taupo, the Gisborne high country, Hawke’s Bay, Manawatu, and the mid Canterbury coast. In contrast, winter rainfall was below normal in Northland, Thames-Coromandel, Western Bay of Plenty, much of Auckland, Nelson, and much of Marlborough and Otago.

Temperature

Seasonal mean temperatures were near normal for New Zealand overall. However, they were at least 0.5 °C below normal in much of the north and west of the North Island from Northland to Horowhenua, and also below normal in Buller, South Canterbury and east Otago.

Sunshine

Winter sunshine hours were at least 120 percent of normal in the north and west of the North Island from Northland to Wellington, and in the east of the South Island from inland South Canterbury to Southland. It was also sunny, with at least 110 percent of normal hours in most other regions. In Dargaville, Hamilton, New Plymouth, Dunedin and Invercargill it was the sunniest winter on record.

For full details see http://www.niwascience.co.nz/ncc/cs/sclimsum_06_3_winter.pdf

For further information, contact Dr Jim Salinger – Principal Scientist, Climate NIWA National Climate Centre j.salinger@...

Stuart Burgess – Climatologist– Wellington  s.burgess@...

Geoff Baird – Communications Manager -  g.baird@...

Acknowledgement of NIWA as the source is required.

NOTABLE WEATHER EVENTS OF WINTER 2006 (Ben Tichborne)

The winter of 2006 was a memorable one, with much stormy and disruptive weather. A very cold June will be especially remembered for the severe snowstorm which smothered Canterbury, while the lower North Island was plagued by heavy rain in July and August, resulting in damaging slips and flooding.

JUNE 2006

# 1st - Extensive fog in Central Otago and Southern Lakes valleys and basins. Only 4C max in Alexandra.

# 4th/5th - Very cold southerly outbreak spreading over South Island (evening 4th) and North Island. (5th) Snow showers to low levels in some eastern and southern parts of South Island. Snow and ice cause problems on Dunedin's hill suburbs, while lighter falls dust Christchurch's Port Hills and rural areas just inland from the city. Light snow falls on southern and central North Island high country, with a few centimetres at the summit of the Rimutaka Hill Road and on the Desert Road, but with no disruption to motorists. Only 3C in Kelburn at 9am. However, only brief snow flurries on Mt Ruapehu.

# 6th - Severe frosts in many areas following clear skies and light winds in wake of previous day's cold southerly, which dies out overnight. -0.5C minimum at Whenuapai; -6C frost at Henderson; -5C frosts at Havelock North, Paraparaumu, and Christchurch Airport.

# 7th-9th - Heavy frosts continue in many areas.

# 11th-13th June - Weather 'bomb' brings stormy weather, including severe snowstorm in South Island. (see details below)

# 14th - Widespread heavy frosts in morning, eg -7C minimum in Waiouru; -13C in Omarama.

# 15th - Westerly gales in the far south. Heavy rain in Fiordland, eg 77mm at Milford Sound.

# 16th - Active trough moves onto NZ. Snow showers in some inland areas of South Island, especially in South Canterbury (eg Tekapo, Fairlie, and Waimate - places still thickly coated from the 12th)

# 17th - Scattered thunder and hail in many parts of North Island, plus snow on central high country. Snow showers also to quite low levels in parts of Otago and Southland.

# 18th - Snow to about 200-300 metres in east and south of South Island. Early morning snow also in inland areas of northern Westland, Buller and the west of the Nelson area. Snow closes roads in central North Island in evening; also reported as low as Kaponga in Taranaki, and is visible on Mt Tarawera near Rotorua from fall on the previous day. Also thunderstorms in places. Lightning strikes a house in Otaki.

# 19th - Deep low moves to northeast of North Island, resulting in southeasterly gales over the island. Damage caused by these gales, especially in Taranaki and Bay of Plentry. Heavy snow about central and Hawkes Bay high country, closing roads. Record low 5.9C maximum in Rotorua, with sleet and snow flurries on higher areas near the the city and also around Taupo. (several centimetres on Mt Tauhara) Severe frosts in many parts of South Island, eg -9C minimum in Fairlie.

# 20th - Heavy frosts in many areas.

# 21st- 24th - Storm brings heavy snow to North Island high country (see details below)

# 25th-28th   - Severe frosts in many parts of both islands, except for east of North Island (where cold, showery southeasterlies continue). -11C minimum in Fairlie (25th); -12C at Tara Hills. (27th) Freezing fogs in many inland valleys and basins of South Island, resulting in temperatures struggling to get above freezing in places, eg only -2C maximum in Alexandra (28th) Morning fog disrupts Wellington Airport. (28th)

# 29th - Overnight rain clearing leads to black ice making roads dangerous in Central Otago. Light snow falls on some South Island high country areas during a weak southerly, eg 2cm on Lindis Pass.

JULY

# 1st - Heavy fog disrupts Wellington Airport in morning; many flights cancelled. More severe frosts in many parts of South Island, eg -7C minimum at Dunedin Airport.

# 2nd - Freezing fog keeps Alexandra from rising above -1C.

# 3rd - Morning fog in Auckland and all day fog in Waikato.

# 4th-6th - Storms bring heavy rain and flooding to lower North Island. (see details below)

# 8th - A period of southwesterly gales about coastal Southland, South Otago, and Dunedin in late afternoon and evening.

# 9th/10th - Heavy rain in Fiordland.

# 12th - Active trough crossing NZ in a west to northwest flow, bring some heavy falls of rain and thunderstorms to many northern and western areas. Heavy hailstorm leaves a snow like coating to part of Hamilton, plus tornado reported near the city. Northwesterly gales about central NZ.

# 13th - Snow above about 600 metres in Otago and Southland, but to lower levels in Fiordland, where people are stranded at Milford Sound due to snow and avalanche danger blocking SH94. Only 3C at Milford Sound at 3pm.

# 14th - Morning fog in parts of Otago and Southland.

# 14th/15th - Heavy rain in east of North Island and hill country west to Taranaki, areas affected by previous big rain event earlier in the month.

# 16th-18th - Extensive areas of fog in both islands, disrupting some airports at times, eg Auckland and Christchurch. Alexandra only reaches 3C on the 17th and 2C the next day, Ashburton only gets to 5C on the 18th, but Kaitaia records an unseasonably warm 21C on the 17th.

# 19th - Heavy snow above about 400 metres in inland Canterbury, eg 50cm at Mt Hutt, and 25cm at Arthurs Pass.

# 20th - Yet more heavy rain in south of North Island, eg Wainui Reservoir 124mm in 24 hours; Waipoapoa (Hawkes Bay) 110mm in 24 hours; Waimarama 99mm in 36 hours. Slip forces evacuation of Eastbourne houses. Southerly gales about Cook Strait, eg 136kph gust at Mt Kaukau.

# 21st - Very cold southerly over NZ with snow showers to low levels in east and south of South Island and hills in southern North Island, including hill suburbs of Dunedin, Port Hills of Christchurch, and even the hill suburbs of Wellington. Falls are mostly too light to cause disruption, but locally heavy snow (about 10cm) affects roads in and around Queenstown in morning. Desert Road closed by ice in early morning and again in evening.

# 22nd - Chilly 11C max in Auckland. Some further light snow in central North Island high country.

# 30th - Heavy rain on South Island West Coast.

# 31st - Warm northwesterly flow over NZ with unseasonable 21C maximums in Kaikoura, Napier, and Hastings.

AUGUST   

# 1st - Warm 19C max in Gisborne in a northwesterly flow. Mild 16-18C maximums in other eastern places.

# 2nd - Heavy rain about Mt Taranaki and East Cape ranges east of Opotiki and north of Gisborne. Warm 21C max in Hastings and 20C in Hastings, as northwesterly flow continues.

# 3rd - Some heavy overnight rain in Hutt Valley due to convergence.

# 4th - A balmy 21C max in Kaitaia. Fog disrupts Auckland International Airport

# 6th - Heavy rain  and northeasterly gales (wind damage in Te Aroha) in many northern parts of North Island, especially areas exposed to the northeast. 24 hour totals of 95mm in Whangarei. 250mm at Pinnacles (Coromandel Peninsula), 138mm in Whitianga, 91mm in Tauranga, 105mm in Whakatane, and 153mm at Poroporo. (near East Cape) Consequent flooding and slips in places. Heavy rain (150-200mm totals) also recorded on Mt Taranaki

# 7th - Warm 20C maximums in Napier and Gisborne following clearance of overnight rain. However, cold southerlies over South Island, with snow gradually lowering on the high country.

# 8th - Further heavy rain causes disruption in central and lower North Island, with many slips occurring on already sodden ground. Snow closes Desert Road for a time in the morning. Persistent rain results in some flooding in parts of Christchurch, especially in the eastern Port Hills where falls are heaviest and the lower Heathcoate breaks it banks.

# 9th - Funnel cloud reported over Pount Chevalier, Auckland.

# 10th - Heavy morning frosts in many parts of South Island, eg -9C minimum in Alexandra; -7C at Dunedin Airport.

# 12th - Cold southwesterlies over South Island with snow showers on the hills and high country, including an evening dusting down as low as 300 metres on outer Banks Peninsula. Christchurch drops from 14C to 8C between 1-2pm.

# 13th Snow to low levels in parts of Southland (settling above about 200m on Hokonui Hills), and other high country areas of both islands.

# 14th - Snow to low levels for a time in Canterbury, including several centimetres on Port Hills in early morning. (settling as low as 100 metres, plus sleet in the city) Thunder and hail showers in west of North Island (heavy hail in Matamata about midafternoon), plus further snow showers on central high country.

# 15th Some further snow showers on central North Island high country in morning. Afternoon thunder and hail in parts of Northland, including a 45 minute hailstorm in Kerikeri.

# 18th - 20C max in Ashburton, in a mild northwesterly flow. Heavy rain in Fiordland (138mm at east side of Homer Tunnel) and Westland (157mm at Waiho)

# 19th - Mild northwesterly flow over NZ. 20C max again in Ashburton and 18-19C maximums in many other eastern places.

# 20th - 20C maximum in Napier.

# 21st/22nd - Very cold south to southwest outbreak sweeps over South Island on 21st and North Island on 22nd. Snow to low levels in many areas, with some heavy falls in Te Anau basin (30cm) and Banks Peninsula. Roads closed on Port Hills and outer peninsula bays, and snow briefly settles in some Christchurch suburbs (overnight 21st/22nd). Dunedin schools closed due to threat of heavy snow (though only a few centimetres settles on hill suburbs) Hail showers in many parts of North Island with snow flurries and sleet to unusually low levels in some southern and central areas on 22nd, eg Stratford, hills near Wanganui, Tokoroa (a light fall for about 5 minutes), and the outskirts of Taupo and Rotorua. Mountainbikers at the first day of World Championships in Rotorua ride through a flurry of snow and hail on Mt Ngongotaha. Heavier snow about central high country, closing SH1 from Rangipo to Taihape and the Napier-Taihape Road. (22nd)

# 23rd - Heavy frosts in many areas in wake of cold southerly outbreak of previous day.

# 24th - Several vehicles are trapped by snow on Desert Road overnight, as moist air with a cold front arrives over existing cold airmass.

# 26th - Low and frontal system crosses central NZ with heavy rain causing yet more flooding and slips, including Wellington. 100mm in 15 hours at Kelburn. 80-100mm in a 9 hour period on Mt Taranaki and Tararuas.

# 28th - Westerly gales in the far south, but Southwest Cape on Stewart Island has gusts up to 166kph.

# 29th-31st - Warm spell in eastern areas to end a not so warm winter. 22C max in Timaru. (29th) 24C max in Kaikoura and 20-22C in many other eastern places. (31st)

# 31st - Westerly gales about Southland, parts of Otago and South Island high country.

MAJOR EVENTS

# 11th-13th June - Weather 'bomb' brings stormy weather, including severe snowstorm in South Island.

This was a major winter storm which caused much damage, especially the severe snowstorm which blanketed Canterbury to sea-level.

A low developed in the Tasman Sea on the 10th and deepened on the 11th. A strong moist northwesterly flow on its eastern side brought heavy rain to Buller and Westland on the 11th, causing flooding in Greymouth. (a small tornado was also reported there) Cold southerlies spread onto the far south in the evening, bringing some snow to low levels in northern Southland.

During the 11th, Canterbury was experiencing mild northwesterlies with temperatures reaching a maximum of 17C in Christchurch. At that time forecasts were warning of snow to about 300 metres in Canterbury for the next day, but what happened that night caught many by surprise as very cold air undercut the existing moist air, and sent temperatures plummeting lower than predicted. For example, at 11pm, Christchurch was still on a mild 14C, but during the early hours it steadily dropped - it was down to 2C by 5am. Heavy snow began falling to sea-level in South Canterbury (and the Waitaki Valley of North Otago) in the early hours of the 12th, and spread north to reach Christchurch by 7am. It continued heavily through to the early afternoon, with accumulations of 38cm in Ashburton (heaviest recorded), about 25cm in Timaru (heaviest for 60 years), and 90cm near Fairlie. However, while much of Christchurch had several centimetres of snow, many eastern suburbs and low lying parts of Banks Peninsula got no snow at all, though heavy falls developed above about 300 metres on the peninsula during the day.

This was a very severe snowstorm, resulting in much damage and disruption. Numerous roads were closed (including SH1 for a while), buildings and trees were damaged by the weight of the snow and thousands lost power and phone links (about 35,000 lost power), even in coastal areas which rarely receive settling snow, let alone heavy dumps. More than 500 power poles were destroyed by the snow. Some homes had to wait three weeks for their electricity to be restored. While actual stock losses were light, the condition of stock was weakened, and farmers had to use up valuable supplies of feed. It is estimated that the snowstorm cost the country's economy more than $100 million.

While the snowstorm was smothering Canterbury, the cold front associated with the low crossed the North Island, accompanied by a period of heavy rain with severe and damaging northwesterly gales in many areas. These gales were believed to have contributed to cable damage in Auckland which resulted in a power cut over a greater part of the city for much of the day.

The snow gradually eased in Canterbury during the afternoon, but another cold front moved onto the South Island at night and crossed the North Island on the 13th. This brought snow flurries to low levels in the east and south of the South Island, but these were only light falls, and confined mostly to exposed places like Banks Peninsula. As the cold southerlies moved onto the North Island, snow fell on the high country, including both the Rimutaka Hill Road and the Desert Road, briefly closing the latter. About 30cm also closed the Napier-Taihape Road, with the heavy snow in that area closing a local school.

Mean sea level pressure analyses for midday NZST 10th June to midday NZST 13th June 2006 in 12 hour steps are shown here.

# 21st- 24th June - Storm brings heavy snow to North Island high country

A trough and low crossed the country during this period, resulting in a very strong and very cold southeasterly flow over the North Island with heavy snow to low levels about the central and eastern high country causing much disruption.

During the 21st, a cold front crossed the South Island, followed by a very cold southerly change and snow to low levels in many eastern areas of the South Island. Some heavy falls were reported in inland Canterbury; causing further disruption to areas still affected by the big fall of the the 12th.

The snow showers continued into the next day, with snow settling in parts of Christchurch again for a time in the morning.

Meanwhile, a low formed off the West Coast and moved northeast, resulting in a complex low pressure system over and to the northeast of the North Island on the 22nd. A strong and very cold southeasterly flow enveloped the southern half of the island, and had spread to the whole island by early the next day. Heavy snow fell to low levels about the central and eastern high country, causing much disruption. All roads through the central plateau, the Napier-Taupo Highway, and other routes through the eastern North Island ranges were closed by snow, with snow also blanketing lower towns like Norsewood, Taihape and Mangaweka (and even a few flakes in Taupo on the evening of the 22nd). Temperatures were also unusually cold further north on the 23rd, with dustings of snow on Mt Te Aroha, the higher ranges of the Coromandel Peninsula (settling above about 600m; flakes reported as low as 450m), and even the tops of the Hunua ranges, southeast of Auckland. (which only reached 10C during the day)

At lower levels on the east coast, heavy rain was a problem, causing slips that blocked the highway between Wairoa and Napier.

The flow eased only slowly on the 24th, with further snow on the high country, especially in the east. Several trampers were stranded at Lake Waikaremoana, and drifts over a metre deep were reported on the Napier-Taupo Highway. Heavy rain resulted in slips closing a number of roads in the Gisborne area.

Mean sea level pressure analyses for midday NZST 21st June to midday NZST 24th June 2006 in 12 hour steps are shown here.

# 4th-6th July - Storms bring heavy rain and flooding to lower North Island.

A complex low pressure system stalled over the North Island during this period, resulting in heavy rain and flooding in the lower half of the island, especially in the Wairarapa.

On the 4th, a trough of low pressure crossed the South Island, bringing cold southerlies and snow to about 300 metres in the east, with about 10cm in some inland parts of North Canterbury. Two lows had developed on this trough as it moved onto  the North Island late in the day, one to the west of central New Zealand, and one to the east. Rain and the cold southerly change had spread onto the south of the North Island by the evening.

On the 5th and 6th, the low pressure system had settled over the north of the North Island, with a moist east to southeast flow further south. This brought heavy rain to the south of the island, especially around Wellington and the Wairarapa, eg 140mm in Wainuiomata. Flooding and slips caused considerable disruption, especially in the Wairarapa (SH2 closed north of Masterton and Martinborough isolated for a time) and in the Wanganui area. (Waitotara and Whangaehu rivers flooded) 

Meanwhile, southerly gales through Cook Strait forced the cancellation of a number of Interislander ferries due to large swells. In the central North Island, snow closed the Desert Road for a time on the 6th, while a number of skiers were trapped at the Turoa and Whakapapa skifields on Mt Ruapehu by heavy snow on the same day.

Lingering cold southerlies brought light snow to low levels in Canterbury early on the 5th, including a dusting on the Port Hills. Further south and inland, heavy frosts added yet more discomfort to residents continuing to suffer the very cold winter weather.

Mean sea level pressure analyses for midday NZST 4th July to midday NZST 6th July 2006 in 12 hour steps are shown here.

CHRISTCHURCH WEATHER  - WINTER 2006  (Ben Tichborne)

JUNE

Winter arrived early with a vengeance this year, with very cold tempertures and a severe snowstorm in Canterbury.

The first 10 days of the month were mostly settled. However, a spell of very cold southerlies occurred on the 4th and 5th, bringing sleet to Christchurch, and a light dusting of snow to the Port Hills and rural outskirts of the city overnight on the 5th. From the 6th to the 10th, nights were consistently frosty, but day tempertures were rather mild.

On the 11th, a mild northwesterly flow covered Canterbury, ahead of a deepening low in the Tasman Sea. Overnight 11th/12th, the low moved onto the upper South Island, with a very cold southerly flow developing further south. Snow was forecast to 300 metres, but what eventuated was far worse. The cold air undercut the moisture from the low, resulting a severe snowstorm over much of Canterbury. The worst snow was in mid and South Canterbury, with near record dumpings of about 25cm in Timaru, and 75cm in Fairlie. But Christchurch didn't escape, with several centimetres blanketing a large part of the city, though surprisingly many eastern suburbs didn't get any snow. Banks Peninsula also escaped the snow at lower levels, but heavy falls developed above about 300m during the day. The snow caused much disruption to rural Canterbury, with buildings and trees damaged, roads blocked, and thousands of households without power. (some for several weeks) Light snow flurries and sleet also fell to sea-level in parts of Christchurch and Banks Peninsula on the morning of the 13th.

The rest of the month remained very cold and saw a mixture of damp southerlies alternating with some fine frosty spells. (and severe frosts) Snow fell to low levels in parts of Canterbury again on the 16th, 18th/19th, and 21st/22nd, but not nearly as heavy as the 12th. (though adding to the misery of those affected by the big dump) Light snow settled in Christchurch for a time on the morning of the 22nd.

JULY

Changeable weather dominated this month, with unsettled periods and onshore flows delivering some rain or drizzle, but also some fine intervals. In other words, fairly normal weather for mid winter. Two very cold southerly outbreaks brought snow to the Port Hills and sleet to the city on the 4th/5th and 20th/21st. Heavy snow also fell about the inland high country on the 19th.

AUGUST

Unsettled periods were again dominant, resulting in a wetter than normal month. There were three main wet spells: 1. 6th-8th - Persistent rain affected Christchurch with some surface flooding. Heaviest falls of up to 90mm were recorded about the eastern Port Hills, resulting in slips and flooding of the lower Heathcoate River. 2. 13th/14th - Period of rain in the city with a little hail and sleet. Heaviest about the Port Hills, where snow lowered to about 100m for a time in the early morning of the 14th. 3. 21st/22nd - A very cold southerly outbreak sees rain turning to snow and sleet late evening of the 21st; snow settling above about 200m on Port Hills by morning of 22nd. Some further hail and sleet showers that day.

By contrast, the 19th was a mild day with northwesterlies pushing temperatures up to 19C, and westerly and northwesterly flows prevailed from the 28th, with mild daytime maximums (reaching 20C on the 29th) ending a winter that will be more remembered for its cold and wet weather.

Next News Email will have the news clippings.