Evaluating South African Weather Service information on Idai tropical cyclone and KwaZulu-Natal flood events (with corrigendum)

Abstract

Severe weather events associated with strong winds and flooding can cause fatalities, injuries and damage to property. Detailed and accurate weather forecasts that are issued and communicated timeously, and actioned upon, can reduce the impact of these events. The responsibility to provide such forecasts usually lies with government departments or state-owned entities; in South Africa that responsibility lies with the South African Weather Service (SAWS). SAWS is also a regional specialised meteorological centre and therefore provides weather information to meteorological services within the Southern African Development Community (SADC). We evaluated SAWS weather information using near real-time observations and models on the nowcasting to short-range forecasting timescales during two extreme events. These are the Idai tropical cyclone in March 2019 which impacted Mozambique, Zimbabwe and Malawi resulting in over 1000 deaths, and the floods over the KwaZulu-Natal (KZN) province in April 2019 that caused over 70 deaths. Our results show that weather models gave an indication of these systems in advance, with warnings issued at least 2 days in advance in the case of Idai and 1 day in advance for the KZN floods. Nowcasting systems were also in place for detailed warnings to be provided as events progressed. Shortcomings in model simulations were shown, in particular on locating the KZN flood event properly and over/underestimation of the event. The impacts experienced during the two events indicate that more needs to be done to increase weather awareness, and build disaster risk management systems, including disaster preparedness and risk reduction.

Flood hazard management in a multiple hazard context: a systematic review of flood hazard management during the COVID-19 pandemic in Africa

“…Aside from material destruction, several aspects of repercussions from flood risk in -Western Africa include health impacts and economic losses [ 44 ]. The South-Eastern part of Africa has previously been hit by severe cyclones, exacerbating the COVID-19 disease and flooding damage [ 5 , 10 ]. Poor communities are defenceless due to the exposure of their livelihoods to flood impacts, particularly in rural locations with limited access to services and infrastructure [ 19 ].…”

“…Research emphasizing the relationship between flood hazards and the impacts on the African continent is long-standing [ 5 , 17 , 26 , 32 , 33 , 37 ]. Wagner and others [ 44 ] did a systematic review of flood management in West Africa.…”

Literature survey of subseasonal‐to‐seasonal predictions in the southern hemisphere

“…Most of African countries are dependent on rain-fed agricultural activities and are vulnerable to climate extreme events that have detrimental socioeconomic impacts. Moreover, there is a need to develop temperature and rainfall prediction systems at S2S timescales in the African region, particularly to facility readiness for high-impact events such as flood events along the Mozambique coast (e.g., Tropical Cyclone Idai) and the eastern coast of South Africa as have happened in April 2019 (Bopape et al, 2021). Furthermore, it is imperative that governments in the region invest more resources in S2S prediction studies, particularly with the changing climate challenges that the world is facing.…”

Assessment and prediction of flood hazards using standardized precipitation index—A case study of eThekwini metropolitan area

“…It is important for disaster management practitioners to learn from lessons in order to adapt good practices. This is the case with cyclone Idai that caused floods over Mozambique, Zimbabwe and Malawi resulting in hundreds of death and the KwaZulu-Natal (KZN) flood events soon afterwards causing death and destruction (Bopape et al, 2021). Research conducted by Bopape et al (2021) showed warnings of the events were given 2 and 1 day respectively and that there were shortcomings in locating the KZN floods indicating that the impacts experienced during the two events could have been minimized if long notices of the event were received.…”