There was a large area of convection north of Cocos Island for some days prior to the formation of Dan . On 14 December a tropical low, which could be identified in the general area of convection, moved steadily eastwards. During the 15 th the centre turned to the southwest and slowly intensified. Peak intensity occurred during 16 December with an estimated central pressure of 980 hPa and maximum winds of about 100 km/h. Cyclone Dan then moved in an erratic path and passed about 140 km to the west of Christmas Island on the morning of the 17 th, where north-west winds of up to 74 km/h were recorded.
Dan did not develop into a severe cyclone and was one of the less common types of cyclones encountered in this Region, in that it had an overall south-easterly track during its lifetime. This track was due to the circulation of cyclone Carol which was moving westwards about 800 km south of Dan . As Dan neared Carol during 16 to 18 December, it encountered a region of increased vertical shear which caused a rapid dissipation as the upper portion of Dan sheared to the southeast. The low-level circulation finally dissipated about 370 km south of Christmas Island.