The first named storm of the 2021–22 South-West Indian Ocean cyclone season, Ana developed from an area of convection that was designated as Invest 93S northeast of Madagascar.

[2] At 07:30 UTC on 20 January, the Joint Typhoon Warning Center reported a formation of an area of convection, which they designated as Invest 93S, approximately 378 nmi (700 km; 435 mi) from Mauritius, with the agency giving a low chance for potential tropical cyclogenesis within the next 24 hours.

[4] By the evening, the JTWC upgraded the system to a medium chance for potential tropical cyclogenesis, after noticing its obscure low-level circulation (LLC).

[7] Twelve hours later, the MFR upgraded it to tropical disturbance status, as they found that the system's cloud pattern had improved.

[8] The disturbance slowly consolidated into a defined convective structure while also developing distinct curved rainbands, which prompted the MFR to upgrade it to a tropical depression by 06:00 UTC on 22 January.

[10][11] Because of the mountainous terrain of Madagascar, the system weakened a bit but still managed to preserve its organized convection and its low-level center.

This occurred after entering the Mozambique Channel, where more conductive environmental conditions were available along with good convergence of monsoonal flow.