490 



NATURE 



[March 24, 1892 



inscriptions from the ancient empire that the risings of 

 Orion and Sirius were already attentively followed and 

 mythologically utilized at the time of the building of the 

 pyramids." i 



{To 



J. Norman Lockyer. 

 ■;oniinueci.) 



THE WINTER STORMS OF NORTHERN 

 INDIA. 



'T^HE physical constitution and history of the storms 

 -»• of India and Indian Seas is a subject which, 

 almost from his first association with the Indian 

 Meteorological Department, Mr. Eliot has made pecu- 

 liarly his own. Besides nine elaborate, and, as far 

 as possible, exhaustive, memoirs and reports on the 

 history of particular storms, two on the tracks and 

 periodicity of the cyclones of the Bay of Bengal during 

 the ten years 1877-1886, and an admirable hand-book, in 

 which he has summarized, for the guidance of seamen, the 

 characteristic features and behaviour of these storms, his 

 annual reports on the meteorology of India have always 

 been replete with the results of his studies of the storms 

 of the current year ; and to him is mainly due that 

 development which has been effected in the system of 

 storm warnings for the coasts of India in recent years 

 and has rendered it one of the most efficient and com- 

 prehensive organizations for that purpose now in opera- 

 tion in any part of the world. 



Like most other features of the climate, the storms of 

 India differ very greatly in their leading characteristics at 

 different seasons of the year. We have, in the first place, 

 the well-known cyclones and cyclonic storms of the Bay 

 of Bengal and the Arabian Sea, which are most frequent 

 when the summer monsoon is at its height, and most 

 severe at its commencement and termination. These are 

 generated^over some part of the tropical sea north of 

 latitude 6^, and travel, as is now well known, on tracks 

 between west and north— most frequently north-west 

 or west-north-west ; sometimes, however, in the spring 

 and later months of the year, recurving to north-north- 

 east or even north-east, as they approach the tropic. In 

 vutue of their severity and destructiveness, these storms 

 have attracted far more attention than any others, and 

 not only Piddington's, but also the writings of most of 

 his successors, have been almost exclusively devoted to 

 them. 



Of a very different type are the storms that bring the I 

 rainfall of the cold season and the earlier spring months ' 

 to Northern India. It would be incorrect to speak of i 

 these as the storms of the winter monsoon (unless the : 

 term be understood, in its strictly etymological sense, as 

 merely the name for a season of the year), for during their i 

 passage the northerly winds are suspended over a great 

 part of India, and, with the rarest exceptions, they never 

 penetrate far into the- tropics. These storms, if they 

 travel, always move from west to east. They have the 

 usual cyclonic constitution, but the winds have but little 

 force ; and it was not until the preparation of daily weather 

 charts for the first time showed their true nature, that 

 this fact was even suspected. 



Many of the features of these cold-weather storms are 

 very striking and characteristic, a-nd, as has been re- 

 marked by Mr. Eliot in his reports for 1888 and 1889 the 

 temperature of Northern India in the cold seasok is 

 chiefly determined by their number and character Each 

 of them is preceded by a wave of high temperature, and 

 toUowed by a cold wave ; except,indeed - and the exception 

 IS instructive— when the course of the storm is so far 

 south of the Himalayas that little or no snow falls on the 

 mountains (see " Climates and Weather of India," p. 206). 



^ Krall, op. cii., p. 45. See also Brugsch, 



NO. I 169, VOL. 45] 



Aeg.Zait.," 



In these cases, which are, however, exceptional, the cold 

 wave is sometimes evanescent. On the other hand, as 

 Mr. Eliot remarks, " the intensity and period [of the cold 

 wave] largely depend on the amount of rainfall in Northern 

 India and of the snowfall on the Himalayan mountain 

 regions, and the height to which the snow-line has 

 descended." As a rule, therefore, the cold wave follows 

 the storm. Mr. Eliot gives, in his report, a table of the 

 changes of temperature from day to day from January 20, 

 to February 7, 1889, which includes two very characteristic 

 illustrations of this phenomenon, and which therefore we 

 extract. The figures show the variations of the observed 

 mean temperature of each day from the average of many 

 years for the same day. The crest of each warm wave is 

 emphasized by strong type and the trough of each cold 

 wave by italics. 



The history of these two storms is as follows, and it 

 exhibits one or two remarkable and suggestive features 

 which will presently be noticed more particularly. The 

 first disturbance originated (or made its first appearance 

 in India) on January 22. There were two separate centres 

 and areas of disturbance, one of which covered the 

 Punjab Himalaya and adjacent plains from Sialkote to 

 Roorkee. This filled up [apparently] on the 23rd, after 

 giving moderate snow on the hills and light showers on 

 the adjacent plains. The other originated in Rajputana, 

 and advanced, on the 23rd and 24th, in an easterly direc- 

 tion, across Northern India into Burma. It gave moderate 

 general rain to the North-West Provinces and Central 

 India, and light showers to Behar, Bengal, and Assam. 

 This first storm was therefore of very moderate intensity. 

 The snowfall and rainfall were but slight, and in the 

 Punjab, Bengal, and Burma insufficient to bring down the 

 temperature below the normal average. 



The second disturbance was one of greater intensity, but 

 like its predecessor had a double centre. One part con- 

 sisted of a shallow depression, which passed into Sind 

 from Baluchistan on the 28th, advanced through Central 

 India, Behar, and Bengal, on the three following days, 

 and into Burma on P^ebruary i, where it slowly filled up 

 during the next three days. The other part was a deep 

 depression, which formed in the Northern Punjab on the 

 evening of the 28th, and during the next thirty-six hours 

 marched slowly to the south-east along the southern face 

 of the Punjab Himalayas. It filled up very rapidly on the 

 evening of the 30th, and morning of the 31st of January, 

 in the South-Eastern Punjab. The double disturbance 

 gave a very heavy fall of snow over the whole of the 

 Western Himalaya, bringing the snow-line down to 3500 

 or 4000 feet, and also general rain to nearly the whole of 

 Northern and Central India, which was greatest in amount 

 in the Punjab, the North-West Provinces, and Behar. 

 As is shown by the table (see next page), the fall of 

 temperature after this storm was proportionately great, 

 amounting to 9*° in the Punjab, and to 14^ or 15° on the 

 mean of the day in Guzerat, Central India, and the Central 

 Provinces. It continued three or four days after the 

 weather had cleared up, so that the trough of the cold 

 wave followed the crest of the warm wave after an interval 

 of five or six days, and each occupied three or four days in 

 passing from the Punjab to Burma. Mr. Eliot gives eight 

 charts in illustration of these waves, of which we reproduce 

 those for January 30 and 31 and February i. They 

 are projected for the observed temperatures at 8 a.m. of 

 those days, and show, not the temperatures themselves, 

 but the amounts by which these deviate in excess or 

 defect from the averages of many years at the same hour. 

 The isabnormals of deficient temperature are represented 

 by broken, those of excessive temperature by continuous 

 lines. 



Mr. Eliot remarks that in the warm waves the greatest 

 excess is generally exhibited by the night temperatures ; 

 and in a table which he gives of the deviations of the 

 daily maxima and minima from their respective normal 



