697624-1873-Balasore-Cyclone-Meteorological-Notice- — Page 1

Ap. 39.

THE HONGKONG GOVERNMENT GAZETTE, 15TH MARCH, 1873.

GOVERNMENT NOTIFICATION.

117

The following Extract from the Report on the late Balasore Cyclone by Mr. WILLSON, Officiating Meteorological Reporter to the Government of Bengal, is published for general information.

By Command,

Colonial Secretary's Office, Hongkong, 15th March, 1873.

EXTRACT.

CECIL C. SMITH, Acting Colonial Secretary.

43. It may be well here to draw attention to those indications of the formation of a cyclonic vortex in the north of the Bay and some of the laws of such storms (determined by the researches al experience of Mr. Blanford, Colonel Gastrell, and others) which appear to have been specially verified by the experience of the late cyclone. These are all practical rules, and are independent of the various theories which may be set forward by different persons to attempt to account for the

nation and course of a cyclone.

I

41 Indications of the probable formation of a cyclone in the north of the Bay during the months of May and June:-

1. The barometer falls steadily for some days round the north of the Bay. The fall occurs first to the south-east at Chittagong and Akyab, and afterwards at Saugor Island, Cuttack, and Calcutta. The barometer at Saugor Island ranges lower than the barometer at Calcutta, (normally, at this season, it ranges higher).

As the disturb- II. At Calcutta the winds become light and variable from S.E. round to N.E. ince increases, masses of clouds drift from E.N.E. or N.E., and as the storm approaches, showers are frequent and the wind blows in gusts.

III. At Saugor Island the winds are at first light, and variable, working round from S.E. to N.E. As the disturbance increases, and as the storm approaches, the barometer continues to fall steadily; the wind increases in force with squalls from the N. E., and masses of clouds float rapidly from the same direction. Outside there is a heavy southerly swell.

IV. At Cuttack, or False Point, the winds are at first light and variable from N.N.E., working gradually round through N. to W. and W.S.W. As the storin approaches, the wind increases in force with squalls from W. and N.N.W.

V. At Chittagong the winds are light and very variable, mostly from S. E. and N.E.

VI. At Akyab the winds are at first light and saturated with moisture, mostly from S. and S.E. As the disturbance increases, the wind increases in force, and works gradually round from S. E. to S. and S.S.W.

VII. In the Bay, along and south of a line drawn from about False Point to Cheduba Island, south-westerly gales, accompanied with torrents of rain, prevail. Standing northwards the barometer talls, and rises when standing southwards.

45. Under the circumstances above specified (III), it, appears unwise for ships in a good anchor- age at Sangor to put to sea. The great danger is that they may be caught in a cyclone before they have got sea room to avoid it. Moreover, the pilot vessels will, under the circumstances, be generally off their stations, and ships will be unable to land their Pilots. It should be remembered also that generally the worst part of a cyclone is the heavy cross sea which accompanies it. In the late cyclone it was this tremendous sea, which is reported never to have been equalled in the Bay, which did such damage. It is accounted for by the long-continued gales from the S.W. This danger would be avoided. by not putting to sea until the weather improved. From (VII) the following would appear to be a de rule. Ships coming up the Bay in the months of May and June with fresh south-westerly gales, gecompanied by torrents of rain and a falling barometer, should not press northwards until the weather ing cores and the barometer rises steadily.

clonic storms.

46. I wish to draw particular attention to the following modern development of the laws of "The direction Disregard of this law may lead, and has led, to many losses at sea. the wind, especially at a distance, is far from being at right angles to the bearing of the centre. The wind does not revolve round the vortex in circles, but along incurving spirals, differing two, tre, or more points, from the tangential circular direction." For example, a ship running up the Bay with a S. W. gale, squalls, torrents of rain, a barometer falling rapidly, and every appearance of esclone has no right to conclude that the centre bears N.W. and that therefore a N. or N.NE. The centre, if at a distance, may bear N. or N.N.E., and a northerly course "The safest course seems run the ship into it particularly as it may be then almost stationary. be to lie to and watch the barometer and wind till the bearing of the centre be known with some It must be borne in mind that before any vortex is formed gales blow towards and round considerable belt of low pressure.

The following rule is I think a safe one when within the influ-

mirse is a safe one.

certainty.

er of a vortex. To find the bearing of the centre, stand with your face to the wind and measure food to your right kand side about ten points. In the southern hemisphere the ten points should be

asured round to the left.