The role of UAVs in Cyclone Gita response and recovery in Tonga

Monday 12 February 2018.  This is a day that many Tongans will not forget. On this day, Tonga was hit by the strongest tropical cyclone (known as Cyclone Gita) in many decades with wind speeds reaching up to 233 km/h. The centre of the cyclone was ~100km in diameter and passed just south from Tonga’s capital, Nuku’alofa.

Similar to the Pacific island countries of Fiji and Vanuatu (discussed here and here in my previous posts), Tonga is also located on the Pacific Ring of Fire, facing the same forms of natural hazards on a regular basis. However, this was the first time in living memory that such a strong cyclone hit Tonga’s main island, Tongatapu, where the majority of the country’s population lives. It was estimated that the cyclone affected around 80,000 people (80 percent of Tonga’s population) and over 800 houses were destroyed and 4,000 damaged.

In the morning of the expected arrival of the cyclone, the Tongan Government issued a 28-day Declaration of State of Emergency and encouraged people to seek shelter in one of the 120 evacuation centres it had established. This preparedness was certainly one of the reasons why no life was lost during the cyclone. Furthermore, only a few months after the cyclone, the Tongan Government released a “Post Disaster Rapid Assessment” – a detailed document indicating the totality of damage done, from infrastructure to economic loss. How was the government so quick and detailed in assessing the damage?

The answer lies in the funding and support that was received by the Tongan Government from the World Bank and its partners, including Australia, New Zealand, the Asian Development Bank, Japan International Cooperation Agency, the European Union and the United Nations Development Programme. Support was not only provided after the cyclone hit, but already beforehand, in anticipation of need.

In early 2017, the UAV4Resilience (Utilising Unmanned Aerial Vehicles for Disaster Assessments in the Pacific Islands) project was launched. The aim of the program was to develop the capacity and readiness of Pacific Island countries to deploy UAVs, specifically drones, for disaster and rapid identification of damage post-disasters. As part of the project, a Brisbane-based tech company V-TOL Aerospace was contracted to develop UVA capabilities for these small countries. The company also received a grant from the Advance Queensland Ignite Ideas Fund, which allowed it to improve the drones so they are capable of instant processing of the visual data it has received (called: VEURON technology). Once the drones were completed, these were sent to Tonga in October 2018, to collect imagery and process these into photographic baseline maps, later to be used by damage assessment teams during recovery efforts.

Drone developed by V-TOL Aerospace

Once the cyclone hit Tonga, within the initial 72 hours, with assistance from the World Bank and the Australian Government, V-TOL Aerospace transported a number of drones to Tonga to assess the damage. Although it was also possible to reach imagery from satellites – because of the high cloud coverage post-Gita, satellite imagery was not detailed enough. This is also something that could remain an ongoing issue for tropical island countries such as Tonga, especially during rainy season.

Hence, to capture detailed high resolution imagery – drones were arranged to capture imagery below the clouds. Within 5 days, the drones collected imagery from an area of 270km2, which means they had successfully mapped the entire island of Tongatapu. Once the imagery was processed and compared to the imagery collected in October 2017, it became evident which areas (i.e. buildings, infrastructure, vegetation) were most damaged and in need of support. The data that was collected and generated through the UAV4Resilience project was then used by the Tongan Government to produce the in-depth “Post Disaster Rapid Assessment” mentioned earlier and to efficiently start the reconstruction and recovery process.

It is worth mentioning that while the manner in which UAVs were used in Tonga was innovative, it was not the first time UAVs have been used in disaster preparedness and response. For example, drone UAVs were used in 2015 when Cyclone Pam hit Vanuatu. The usage of UAVs, such as drones has played an increasing role in the field of ICT4D for years, as discussed by Heeks (2017) in his book “Information and Communication Technology for Development”. And we can definitely only expect to see the number of UAVs used in such situations to grow.