inactive trend seen by several years prior; however, it was slightly more active than the previous year. Throughout the season, an eastward shift in the Hadley Circulation led to an eastward displacement of the subtropical jet maximum, placing it near the Tasman Sea, similar to what takes place during an El Niño (ENSO) event. However, ENSO indexes were neutral during the season. This displacement of the subtropical jet resulted in the regular formation of strong mid-level troughs across Australia and the South Pacific, leading to an abundance of moderate to strong wind shear. Additionally, these systems brought pulses of dry mid-level air that moved as far north as 10°S. This was reflected by the below-average monthly relative humidity values across the basin. Sea surface temperatures were also generally slightly below-average through January 2002 and only slight warming took place during the remainder of the season. The development of cyclones during the season was mainly, aside from Trina, tied into Madden–Julian oscillation (MJO) phases. Trina developed prior to the arrival of the first MJO pulse which reached the basin in early December. This first pulse led to the development of several equatorial Rossby waves – the formations of Cyclones Vicky and Waka were related to these waves. The second pulse arrived in mid-February and was associated with the development of Cyclones Claudia and Des. Systems Tropical Cyclone Trina The first tropical cyclone of the season, Trina formed upper-level low-pressure system on November 29 near the island of Rarotonga. Remaining nearly stationary, the storm meandered in the same general area for over a week. Due to unfavorable conditions for tropical cyclogenesis, the storm struggled to develop significant convection, preventing it from intensifying beyond 65 km/h (40 mph). After finally succumbing to wind shear on December 2, the system weakened to a tropical depression near Mangaia and dissipated several days later. Due to the slow movement of the storm, it produced substantial rainfall over the island of Mangaia, resulting in some of the worst flooding in 50 years. Although no people were killed, nearly 60% of the islands' livestock died and 90% of the staple crop was lost. Estimates from the Cook Islands National Disaster Management Council placed damage at $52,000. Severe Tropical Cyclone Waka Waka originated in a near-equatorial trough of low pressure in mid-December 2001, although the system remained disorganized for more than a week. The storm gradually matured and attained