Tropical Cyclones

 

On average, Tonga experiences 17 tropical cyclones per decade, 1.3 per year with most occurring between November and April. From  1970 to  2020, 72 tropical storms have passed the Nuku'alofa within a 300 km radius. Nine storm-related impacts have severely affected Tonga in the last 40 years, which equates to a storm impact roughly every four to five years, a very high frequency.  According to an estimate, Tonga is likely to sustain USD 9.5 million in damages due to cyclones annually. Tropical cyclone frequency is projected to decrease in the South-East Pacific Ocean basin in the 21st century with moderate confidence. Nearly two-thirds of all projections show either no change or a decrease in tropical cyclone formations. The Pacific DesInventar data for Tonga (1833-2014) reveals 85 tropical cyclone deaths and total cumulative damages of USD 246 million.  On average, USD 15.5 million per year in earthquake and tropical cyclone-related losses. During 2018 Tropical Cyclone Gita, nearly 80,000 people were affected and power lines, schools, agriculture, and infrastructure were damaged. With 800 houses destroyed and another 4,000 damaged, TC Gita was one of the costliest disasters in Tonga with an estimate of USD 164.1 million (i.e., 37.8% of the nominal GDP). During Tropical Cyclone Ian in 2014, almost 70% of the inhabitants of Tonga’s Ha’apai island group i.e., around 5,500 people were affected and caused an economic loss of USD 50 million (11% of the country’s GDP).