CLIMATOLOGICAL HAZARDS

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Overview

Natural hazards are precursors or catalysts for the onset of natural disasters, as highlighted by Chaudhary and Piracha in their 2021 research. These hazards act as the initial stages in a sequence that can ultimately lead to the development of significant natural disasters. The United Nations Statistical Division (UNSD) provides a comprehensive definition of climatological hazards, characterising them as meso- to macro-scale atmospheric processes encompassing a wide spectrum of temporal scales, ranging from intra-seasonal variations to multi-decadal climate variability. These atmospheric phenomena include events such as droughts, wildfires, glacial movement and glacial lake outburst.

Droughts are periods of abnormally low precipitation or no precipitation compared to the average rainfall levels in an area. Droughts often lead to water shortages which have a detrimental impact on the environment, economy, society and agriculture. Droughts are also considered to be multifaceted natural hazards, given their variability duration, severity, and the geographical extent of their impact. Wildfires, also known as forest fires or veld fires, are highly destructive fires that burn uncontrollably and rapidly. Wildfires occur in natural vegetated environments, namely in forests and grasslands. These wildly burning fires (as is suggested by the name) are not easily put out or stopped and, therefore pose significant risks to both the environment and human communities.

Wildfires occur within natural vegetated ecosystems, primarily in forested and grassland environments. These fires, aptly named for their uncontrolled and rapidly burning nature, can be caused by both natural factors and anthropogenic activities. Wildfires are remarkably challenging to extinguish or contain, these fires present substantial hazards, endangering both the natural environment and human communities.

In the South African context, glacial movements and glacial lake outbursts hold no relevance, primarily due to South Africa’s geographical location as a subtropical region that lacks any glaciated terrain. Therefore, the focus of this blog will be directed towards wildfires. More information on droughts can be accessed here (LINK)

South African Wildfire Records

The Global Assessment Report (GAR) Risk Data Platform, has documented that South Africa records an annual average of 41 568 wildfires. The source, location and intensity of the wildfires are not listed on this platform. The GAR Risk Data Platform only provides data on the number of fires that have occurred within the country (Fig 2) as well as disaggregates it to the provincial level (Fig 2). The wildfire events are grouped based on the presence or absence of protected areas in a region as delineated in the World Database on Protected Areas (WDPA), as well as within forested regions.

The fire data on the platform is derived from the MODIS Collection 6 Active Fire Product MCD14ML. The records presented on the platform includes both annual fire data, cumulatively compiled from monthly fire records, as well as data specifically pertaining to fires occurring in critical regions such as forests, protected areas designated in the World Database on Protected Areas (WDPA), and forests located within protected areas.

The fire records contained within this dataset are not restricted to wildfires (vegetation fires). Instead, they include fires associated with active volcanoes, other static land sources, and offshore fires. This variation in recorded fire events accounts for the notably high volume of fire data available on the platform.

Knysna Fire

On the 7th of June 2017, the country witnessed the ignition of one of the most significant fire hazards in recent history: the Knysna Fires in the Western Cape. Over the course of their 11-day duration, these fires consumed more than 100 kilometres of land. The cause of the fires was primarily attributed to natural factors (drought like conditions, high temperatures and strong Berg winds) and were exacerbated by environmental conditions such as dry vegetation, strong winds, low soil moisture levels, and elevated temperatures. These factors collectively contributed to the development of smaller fires (which eventually merged into one big fire) as well as to the rapid and uncontrollable spread of the fires.

As the fires swept through the Greater Knysna areas, they left a trail of devastation in their wake. The profound impacts of the fire encompassed loss of life, extensive destruction of homes, the displacement of residents, and the widespread scorching of vegetation.

Impact of the Knysna Fire:

Loss of Life: Tragically, the fires resulted in the deaths of 9 people (EM-DAT).
Property Damage: The fires caused extensive damage to residential properties, businesses, and infrastructure. Approximately 1200 homes were destroyed in the fires.
Environmental Damage: The ecological impact of the fires was great as the fires scorched more than 20 000 hectares of vegetation as well as destroying natural habitats and wildlife.
Community Disruption: Thousands of residents (approximately 5500) were forced to evacuate their homes due to the advancing fires. Emergency shelters were established to provide temporary housing and support for those displaced.
Economic Damage: EM-DAT’s estimation indicates that the economic losses due to structural and environmental damage from the fires exceed a sum of $500,000.

Databases

FIRMS	GAR Risk Data Platform	CAELUM Database	EM-DAT
First Record: 11 Nov 2000	First Record: Jan 2003	First Record: 2 Oct 1989	First Record: 7 Sep 1991
Data Formats: SHP, KML, TXT, WMS	Data Formats: XLS, TXT	Data Formats: XLS, TXT	Data Formats: XLS, TXT, PDF, JPEG
Total number of recorded fires: ~40 000 annually	Total number of recorded fires: ~40 000 annually	Total number of recorded fires: 472	Total number of recorded fires: 10

The FIRMS and GAR Risk Data Platform databases have the highest number of fire records, primarily relying on imagery generated by the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite. This satellite provides high temporal and spatial resolutions, allowing for a revisit to specific sites every one to two days. This capability enables the real-time and near real-time cataloging of fires. However, these records include not only wildfires but also offshore fires, fires associated with volcanic activity, and static land source fires. Therefore, these supplementary sources of fire data contribute to the overestimation of the total number of reported fires by these sites.

In contrast to the aforementioned platforms, the CAELUM dataset fire records exclusively comprises of wildfires. These data are sourced from observations conducted by the South African Weather Services (SAWS), the authorized institution responsible for providing climatological information and data pertaining to South Africa.Therefore, this dataset is held in high regard for its trustworthiness and its provision of precise records.

Moreover, EM-DAT data, in comparison to the data sources listed above, contains a smaller volume of data records. This variability arises from the databases stringent criteria, as previously outlined, which they employ when cataloging hazardous events on their platform. It is for this reason that only fire events meeting the at least one of the specific criteria are included in the EM-DAT database.

Fire Tools

Several tools and technologies are available to detect active fires and monitor their spread. These tools are essential for early warning, fire management, and environmental monitoring. The majority of openly accessible online resources predominantly rely on satellite based remote sensing techniques and systems to detect active fires. The Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) sensors are the most employed satellites for active fires.

MODIS sensors on NASA’s Terra and Aqua satellites provide near real-time data on active fires worldwide. They detect thermal anomalies and can pinpoint the location of fires.
VIIRS: Similar to MODIS, VIIRS sensors on NOAA’s Suomi NPP and JPSS satellites detect fires by measuring thermal radiation.

Tools created with data from these sensors include:

National Disaster Management Center - Fire Early Warning Tool
The tool developed by the National Disaster Management Center (NDMC) offers a daily fire warning index computed through the utilisation of MODIS data. The NDMC is the organisation mandated to provide disaster data as well as resources for the country.This application furnishes users with a fire danger index (FDI) value and local municipal-level predictions. The data is visually represented on a chart and can be filtered to display information pertinent to the specific local municipality of interest.

Data Sources

Additional information pertaining to the likelihood of the occurence of a fire and fire risk can be accessed here:

Data Source	Link	Supplementary Information
CSIR Greenbook	Green Book National Overview	This data product is one of eleven dashboards meticulously designed by the Council of Scientific and Industrial Research (CSIR). Its purpose is to offer a comprehensive overview of the potential effects of climate change and urbanisation on South Africa.
CSIR Greenbook	Municipal Risk Profiles	The Municipal Risk Profiles Tool depicts the likelihood of wildfires and other hazards occurring in a local municipality.
ThinkHazard!	Country Report	ThinkHazard! provides a a general view and the likelihood of occurrence of the natural hazards (including wildfires), for a given location, that should be considered in project design and implementation to promote disaster and climate resilience.