Table 2 World Cup victories by colder and warmer teams

Country and year Temperature characteristics Cold YR Cold SN Warm YR Warm SN

Uruguay 1930 Cold 10 10 a 8

Italy 1938 Warm 10 10 5 6 France 1934 Cold 4 5 11 10

Brazil 1950 Warm 8 8 11 11 Switzerland 1954 Cold 13 12 9 10 Sweden 1958 Cold 10 11 13 12

England 1966 Cold 15 15 12 12

Germany 1974 Cold 21 20 6 7

Chile 1962 Cold 12 14 15 13

Mexico 1970 Warm 12 10 15 17

Argentina 1978 Cold 10 11 19 18 Spain 1982 Warm 22 22 14 14 Mexico 1986 Warm 17 17 23 23 Italy 1990 Warm 22 20 23 25 USA 1994 Warm 28 27 17 17 All colds 95 98 83 80 All warms 120 114 108 113 All World Cups 215 212 191 193

SN is based on a computed ‘football season temperature’. YR is based on the annual average temperature.

World Cups are grouped together there is very little difference (114 cold winners-113 warm winners) between the totals of the two tallies based on the ‘football season temperature’ but when all cold World Cups are put together the colder teams do significantly better (98 cold winners-80 warm winners). This seems to sug- gest that when the tournament is warm this ‘weather factor’ tends to smooth out the dif- ferences between teams and neither has an

advantage; however, it is really in the colder World Cup tournaments that the advantage becomes important. Football is an unpredict- able thing, but then so is the weather.

Reference Bradshaw, M. and Weaver, R. (1993) Physical geogra-

phy: An inmduction to earth environments. Mosby, St. Louis

Severe hailstorm at Grahamstown in relation to convective weather hazards in South Africa

Allen Perry University of Wales, Swansea

A re-evaluation of the frequency of damaging convective storms in South Africa has become possible in recent years. Preston-Whyte and Tyson (1988) noted that “tornadoes are of rela- tively rare occurrence in South Africa”, and in a world-wide review of natural hazards Bryant (1991) considers that “tornadoes are rare on the

Africa continent”. However, D’Abreton (1991) collected data on tornado occurrence from 1984 to 1990 and concluded that “they occur with greater frequency than is generally realised, espe- cially over the Natal interior”. The recent publi- cation of a listing of notable weather events in South Africa from 1500 to 1990 (South African Weather Bureau 1991) allows a considered anal- ysis of both the intensity and frequency of the lightning, hail and tornado hazards. This databank has been analysed for tornadic events by Goliger (1992), but the hailstorm data do not appear to have received the same attention. In this paper it is proposed to analyse the listed data in the light of the suggested T O M 0 hailstorm scale (Webb 1988) and to report on a recent individual storm which occurred outside the area

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of most frequent occurrence and exceeded in intensity any such storm in living memory in the area affected.

Hailstorm chronology

From 1900 to 1990 there are 87 separate listed hailstorm events, which because oftheir intensity were reported in newspapers or articles on weather-related events. Rather more than one third ofthe events occurred in the years 1984-90, suggesting that hail is more frequently noted nowadays and its damage potential in a modern economy is greater than hitherto. Confirmation that severe hailstorms are more often noted comes from the individual annual listings in the Weather Bureau Newsletter. From 1991 to 1993 there were a further 19 damaging hail occur- rences. All these data considered together con- firm the view of Schulze (1965) that “there is no doubt that South Africa is subject to extremely severe hailstorms comparable with those for ex- ample in the mid-western states of the USA and in India”. In a comparative study ofhail in South Africa, Switzerland and Canada (Admirat et ul. 1985), South Africa was found to have the great- est absolute number of hail-days per year. Sur- prisingly, then, the hail hazard in South Africa receives no mention in the recent textbooks on hazards (Smith 1992; Bryant 1991; Alexander 1993), probably because its occurrence is less well known internationally.

Reports in the hail chronology of individual storms killing more than ten people occui- twice, and this can be compared with thc statistic quoted by Alexander that Japan has noted 28 deaths since 1945. Clearly, however, hail fatalities depend on people being caught outdoors or living in vulnerable, flimsy hous- ing. A more objective analysis of large hail can be obtained by using the ‘romo hailstorm intensity scale which relates popular descrip- tion of hail size to an intensity scale. This scale has been used in relation to the South African data for the whole period 1900-93 and the results are shown in Table 1. In some storms where no eyewitness report is available it has been necessary to consider the amount and type of damage in deciding the likely diameter of the hailstones that fell. The two most severe hailstorms were probably those of early

Table 1 93, in relation to the TORRO intensity scale

Severe hailstorms in South Africa, 1900-

Hailstone Diameter No. in South description (mm) Africa, 1900-93 Hen’s egg, small 46-60 22 (41) peach, billiard ball Large peach, 61-80 17 (15) goose’s egg, tennis ball Large orange, 81-100 2 (3) grapefruit Melon 101-1 25 2 (2) Coconut, etc. over 125 2

Figures in brackets refer to storms where an intensity estimate was based on recorded damage.

November 1992 at East Griqualand which killed 14 people, and the storm on 1 February 1936 at Settlers, north of Johannesburg, when ten people were killed.

Geographical distribution of hail and the Grahamstown storm

The greatest frequency of all types of hail in South Africa occurs over the high plateau areas of western Natal and Lesotho. Hail falls mostly during the late afternoon-early evening period, particularly in late spring and summer and is usually associated with thunderstorms. Hail frequency decreases sharply towards the coast. Severe hail events show a concentration in the area of greatest hail frequency and most hail studies in South Africa have concentrated on the Pretoria-Witwatersand area (e.g. Carte and Held 1978).

Severe hailstorm at Grahamstown

Grahamstown has an annual average hail occurrence of only 0.7 days (Stone 1988) and large hail in this part of the eastern Cape Province is rare. The nearest locations that occur in the hail databank are all further inland, e.g. Cradock, Queenstown and Graaff-Reniet. Grahamstown is about 50km from the coast and has a population of about 70000.

On 17 December 1993 a thunderstorm with hail variously described as the size of golf balls and pigeons’ eggs occurred, causing damage to property estimated at hundreds of thousands of Rands. Whole streets of houses had their win-

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dows smashed and hundreds of people were left homeless when shacks on the city's out- skirts were destroyed by the storm. Although no injuries were reported, the storm was the most severe in the area in living memory and of a degree of severity associated with the high plateau areas inland.

On the days preceding the storm a low deepened over the southern Namibian coast and moved southwards and then eastwards. By the 17th this low had moved to the Port Eliz- abeth-East London area and it seems that moisture from the Indian Ocean was probably funnelled into a general convergence area north-east of the low (Fig. 1). The low moved away eastwards over the Indian Ocean on the 18th with light rain over Natal. At Grahams- town 17 December was a hot, rather sultry day with a maximum temperature of 33.3"C after an overnight low of 17.7"C. Such temperature levels are by no means uncommon. At Grahamstown the absolute maximum is 42.3"C, and maximum temperatures exceed 35°C on about five days per year. Following the storms temperatures fell dramatically and

the maximum on 18 December was only 22.4OC.

Conclusion

Severe hailstorms are a more important feature of South African climate than has often been acknowledged. Using the TORRO hailstorm in- tensity scale allows an analysis to be made of the historical chronology of hail, while the severe storm at Grahamstown emphasises that occasional very damaging hail can occur well outside the expected areas of severe hail in the interior of the country.

References Admirat, P., Goyer, G. G., Wojtiw, L., Carte, E. A.,

Roos, D. and Lozowki, E. P. (1985) A comparative study of hailstorms in Switzerland, Canada and South Africa. J. Climawl., 5, pp. 35-51

Alexander, D. (1993) Natural disasters. UCL Press, London, 632 pp.

Bryant, E. A. (1991) Natural hazards. Cambridge Uni- versity Press, 294 pp.

Carte, A. E. and Held, G. (1978) Variability of hail- storms on the South African plateau. J. AppZ.

Fig. 1 &?face pressure chart for 1200 GMT on 17 December 1993

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Meteorol., 11, pp. 165-373 D’Abreton, P. (1991) A svnoptic characterization of

some South ,%can tornadoes, S. Aj?. 3’. Scz., 87, pp. 5G61

Goliger, A. N. (1992) Tornado data-bank. VC’euther Bimazc “CezusIt7ff~il., 12

Preston-Whyte, R. A. and .I‘yson, 1’. D. (1988) Tlic atmosphere mid eueather of .wurlien/ Ajiiia. Oxford University Press, Cape Town, 374 pp.

Schulze, B. R. (1965) Hail and thunderstorm ikquency in South Africa. Kows, 14, pp. 67-70

~~

Smith, K. (1992) Eiivzroriment hazards. Routledge, London, 324 pp.

South &can Weather Bureau (1991) A histoy oj. riotable weather evenu in South Afnca, 1500-1990. Caelum, Pretoria, 125 pp.

Stone (1988) Climate and weather. In: Lubke, R. A. et ul. (Eds.) A $eld ,pi& to the eastern Cape coust, Wildlife Society of South Africa, 520 pp.

Webb, J. D. C. (1988) Hailstorms and intense local rainfalls in the British Isles. J. Meteuml., 13, pp. 166- 182

Some features of Northern Hemisphere weather during winter 1994195

December 1994

The Northern Hemisphere winter months were dominated by the persistent and intense low pressure systems of the North Atlantic and thc North Pacific.

The mean December surface pressure pat- tern showed anomalies below -8 mbar extend- ing from the south of Iceland, across north-east Greenland and into the Norwegian Sea, with a complementing area of negative anomaly (down to -12mbar) south of the Bering Strait. Another area of negative pressure anomaly extended from Mongolia, southwards through western China. Areas of positive pressure anomaly were much less evident; pressure in the Mediterranean Basin was above average, with a maximum anomaly of +7mbar over the Balearics, and further areas of positive anomaly centred over the eastern Canada-US border and north of Hawaii.

Thickness anomalies at 1000-500 mbar were also well marked with peak negative anomalies of -5 dam over Cape Farewell, -7 dam over the Caucasus and -8 dam over the east Siberian Sea; while large positive thickness anomalies covered north-eastern America (with +11 dam over Lake Superior) and China (+8dam over western China).

Across all regions of the UIC mean tempera- tures were above normal with highest maxi- mum temperature anomalies over the south

and east (up to +2.4degC), while northern Scotland recorded a maximum temperature anomaly of only +0.8degC. Minimum tem- perature anomalies followed the same pattern, but with values of +1.6degC for south-east England and only +0.5degC over northern Scotland and Northern Ireland.

Rainfall was above average across all regions of the UK, with East Anglia (59mm, 106 per cent of normal) being the driest region, while western Scotland was wettest with an areal average of 242mm (170 per cent of normal). Consequently, western Scotland was also the dullest region with 22 hours of sunshine for the month (72 per cent of normal), while East Anglia (65 hours, 140 per cent of normal) was the sunniest.

The persistent low pressure across the cen- tral North Atlantic drove mild south-westerly winds into north-west Europe where all areas reported large positive temperature anomalies, ranging from +2.5degC across France, +3.OdegC in Switzerland, to +7.5degC on the Finland-Sweden border, and +5.0 degC fur- ther north over Spitzbergen.

In contrast, negative temperature anomalies occurred across central north Africa, through Egypt, into eastern Turkey (-4.OdegC) and from there across eastern Ukraine to eastern Siberia and Alaska. California and Newfound- land both reported just below normal tempera- tures, but most of Canada, the USA and Mexico were warmer than average, with anom- alies up to +8degC centred over Ontario. Northern India, Malaysia, Vietnam, China and Japan had temperatures averaging 1 to 3 degC above normal.

Rainfall was well below normal over much of

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