Extreme Winds in Argentina Lead to Significant November Dust Event

Extreme winds in southern Argentina led to a significant dust event between November 16-18, 2025. A pronounced subtropical high and strong low pressure system over the Drake Passage led to a very potent jet stream over southern South America. This, in turn, led to intense katabatic winds in the lee of the Andes, reaching 20-30+ meters per second in many areas. These intense winds created a tremendous dust cloud in the region.

Figure 1: NASA GMAO's flagship numerical weather prediction model, GEOS-FP, predicted the wind and dust event in southern South America with a high level of skill. The observed windspeed (shading) and dust aerosol optical thickness (contours) in GEOS-FP Analysis (left panel) are quite close to the forecast from 5 days prior (right panel), as well as the scale of this event.

Though the conditions which led to this massive dust cloud event are common, sometimes causing what are referred to locally as "pomperos," the scale and magnitude in this instance were not. The North-South orientation of the front, the scale of the strong winds, and the relatively little moisture for this type of event of dust created the near-continuous, fast-moving dust cloud. Buenos Aires, Argentina, and Montevideo, Uruguay – located roughly 1600 km away from the source region – were affected buy the dust cloud in less than 24 hours, followed by southeastern Brazil around 36-48 hours after the wind event. GEOS-FP captured this event well, as depicted in Figure 1.