Winds in Stinda Strait 



21 



Frequency of the different wind-intensities (Beaufort) in the Java Sea region. 



1 Karima Strait between the west coast of Borneo and the east coast of Billiton. 



2 Java Sea north of Sunda Strait. 



direction of the wind may change every day and it may happen that a 

 southerly wind in the forenoon may shift to the north in the afternoon, 

 with a short spell of calm between. 



In addition to the monsoons, storms, of which the lower limit of 

 velocity reaches 17 to 23 metres a second, are not uncommon. During 

 a hurricane the velocity rises to 30 or even to 60 metres a second. Of 

 shorter duration and affecting a smaller area are the squalls, sudden 

 gusty winds, which occur on the mountainous coasts of South-east 

 Sumatra and West Java, as in other regions of the Indian Ocean, es- 

 pecially in the monsoon period, with greatest frequency from February 

 to April. The currents in the Sunda Strait are dependent on the winds. 

 They are, however, of the nature of periodic currents. The direction of 

 the current changes daily and during 24 hours there is only one change ; 

 the northerly current brings high tide and the southerly current low 

 tide. The influence of the prevailing wind is generally shown by the 

 fact that during the south-east monsoon the ebb-current flowing to- 

 wards the south-south-west is stronger both in duration and in in- 

 tensity, while during the prevalence of the west monsoon on the other 

 hand the flood-current running towards the north-north-east prevails. 



During the east monsoon, from May to October, the tide flows 

 strongly for 18 hours continuously towards the south-west, during the 

 next 6 hours with less force towards the north-east, or there may be a 



