On 24 November the initial low and the large cloud cluster from which Bert developed were located about 500 km north of Cocos Island. This cloud system was part of a quasistationary convergence zone that extended across Indonesia. Initially the cluster showed little organisation but, early on 26 November, the Geostationary Meteorological Satellite (GMS) imagery showed that cloudbands were becoming more tightly curved.
Cyclonic intensity was reached late on 26 November when the system was located about 850 km northwest of Cocos Island. Bert moved west to southwest and continued to deepen, reaching peak intensity on 29 November with an estimated central pressure of 965 hPa and a max wind of about 150 km/h. On 29 November the system moved to the southeast and then on 1 December it again curved to the west-southwest as it came under influence of a strong high pressure system to the south of the centre.
On 3 December Bert moved into the Mauritius Region as a severe cyclone with an estimated central pressure of 975 hPa and was renamed Christelle. The strongest wind reported was 63 km/h by a ship some 220 km to the south-southwest of the centre at 0000 GMT on 2 December.
No damage or loss of life was reported.