Farahnaz Fazel-Rastgar

Wildfires are increasingly driven by extreme weather and climate variability, posing risks to ecosystems, infrastructure, and human health. This study examines the severe KwaZulu-Natal wildfire of August 4, 2024, using an integrated, process-based framework that combines satellite fire detections, tree cover change data, atmospheric reanalysis, and air quality observations. This study provides a new integrated event-scale assessment of Berg Wind-driven wildfire forcing, atmospheric air-quality impacts, and ecological disturbance associated with an extreme wildfire event in KwaZulu-Natal, South Africa. Analysis of NASA FIRMS and Global Forest Watch data shows that wildfire activity in KwaZulu-Natal is highly episodic, with short-lived but intense fire peaks dominating the seasonal regime. The August 2024 event occurred under anomalously warm winter conditions, extremely low relative humidity, and strong downslope Berg Winds associated with an advancing dry cold front. Reanalysis reveals a coherent atmospheric structure, including a strong surface pressure gradient, upper-level ridging, subsidence, and gusty winds exceeding 20 m s⁻¹, creating conditions conducive to rapid fire ignition and spread. The wildfire substantially degraded air quality, with elevated PM₂.₅ concentrations and enhanced column-integrated organic carbon transported downslope. Tree cover loss analysis indicates that wildfire is an episodic yet significant contributor to long-term forest disturbance, adding pressure to remaining natural ecosystems. These findings highlight the critical role of short-term atmospheric extremes in amplifying wildfire risk, underscore the influence of Berg Wind–dry cold front interactions on fire behaviour, and demonstrate the value of integrating atmospheric forcing into ecological wildfire models, early warning systems, and mitigation strategies in fire-prone regions. By linking drivers, dynamics, and impacts, this work advances process-based ecological modelling of extreme wildfire events.

Namibia, a predominantly hot and arid country, rarely experiences snowfall, which is generally restricted to elevated southern regions during winter. On 5 August 2025, light snowfall and sleet were reported near Aus, representing a rare occurrence of wintertime frozen precipitation associated with atmospheric variability in a subtropical dryland environment. This study investigates the synoptic and thermodynamic conditions associated with the event using ERA5 and documentary evidence from media reports and eyewitness accounts, while acknowledging the absence of official meteorological observations at Aus and the limitations in direct snowfall verification. The analysis identifies a short-lived cold-air intrusion, with 850 hPa temperatures approximately 1.5 K (kelvin) below the 1979–2024 winter climatological mean, representing a notable but not extreme cold anomaly rather than an absolute temperature value. Synoptic analysis indicates that the event occurred within a northward-amplified upper-tropospheric trough associated with negative 500 hPa geopotential height anomalies and enhanced cyclonic circulation over southwestern Africa. The interaction between the amplified trough and a subtropical jet stream exceeding 60 m s⁻¹ contributed to a dynamically favourable environment for large-scale ascent. At lower levels, a strengthened meridional pressure gradient and persistent southerly wind anomalies indicate a deep cold-air intrusion extending through much of the troposphere, consistent with transport of cooler air from higher southern latitudes rather than confirmed Antarctic-origin air. Although mid-level humidity anomalies were modest, transient moisture availability combined with dynamically induced ascent and local orographic effects over elevated terrain likely supported the development of frozen precipitation. The results suggest that snowfall in southern Namibia can occur when moderate cold anomalies, limited moisture availability, and organized synoptic-scale circulation patterns coincide, without requiring record-breaking thermodynamic conditions. However, uncertainties remain regarding the relative contributions of moisture transport, terrain-induced effects, and precipitation microphysical processes because of limited observational coverage and the spatial resolution of reanalysis datasets. This case provides a diagnostic assessment of a rare cold-season precipitation event and demonstrates how naturally occurring atmospheric circulation variability can occasionally produce frozen precipitation in climatologically warm and arid environments.

January 2024 represented an extreme manifestation of the long-term winter warming trend in Iran, characterized by widespread warmth and dryness. During 14–15 January 2024, surface temperatures exceeded climatological means by up to ~ 4 °C, accompanied by reduced mid-tropospheric humidity and below-average precipitation across much of the country, indicating enhanced drought conditions. Synoptic analyses revealed a weakened and eastward-displaced Siberian High, negative sea-level pressure anomalies over northern Eurasia, and a pronounced mid-tropospheric ridge over Iran. At upper levels, strengthening and eastward displacement of the subtropical jet, together with a reversal of 10-hPa zonal winds, confirmed the occurrence of a major split-type Sudden Stratospheric Warming (SSW). The resulting polar vortex split promoted large-scale subsidence and reduced cold-air advection over Iran, leading to adiabatic warming and suppressed precipitation. Statistical analyses further indicate that tropical–extratropical interactions, particularly the Indian Ocean Dipole and the El Niño–Southern Oscillation, modulated the regional temperature response. Overall, this event demonstrates that warm-side surface responses following SSWs constitute an important but underexplored component of winter climate variability over West Asia, capable of amplifying ongoing regional warming and producing contrasting winter anomalies across Eurasia.