The Chilean Meteorological Service (DMC) concluded that the whirlwind that tore roofs off the Alameda bus terminal in Estación Central on Tuesday, October 13, was a gustnado and not a tornado. The classification followed an on-site inspection and an analysis of damage, weather records and videos.
According to T13, Canal 13 meteorologist Michelle Adam warned on the morning show Tu Día that a similar situation could occur again this Tuesday, October 20, with the frontal system affecting the Metropolitan Region.
The DMC had initially suggested that the event could have been an EF0 tornado, the lowest category on the Enhanced Fujita scale, which measures tornado intensity based on damage. The subsequent assessment clarified its nature, according to El Desconcierto.
"The study concluded that the phenomenon recorded on October 13, 2026, at the Alameda bus terminal was a 'gustnado,' a whirlwind associated with the strong gusts generated during a storm," the DMC explained.
The term comes from the English word gust, meaning a sudden burst of wind. Adam described it as a burst of wind that descends from the cloud and looks like a funnel cloud, although "it is neither one nor the other".
The difference lies in where the rotation begins. Meteored, a specialist weather forecasting website, explains that a tornado is a rotating column of air extending from the base of a storm cloud to the ground. A gustnado, by contrast, forms near the surface, along the gust front.
That front develops when cold air descending from the storm reaches the ground and spreads horizontally. When it collides with the surrounding air, it can generate small vortices that do not maintain a vertical connection with the cloud base.
Pamela Henríquez, head of Meteored, said on Tu Día that an expert at the website had already raised that possibility after observing downdrafts mixed with surface winds. Because the damage did not extend to other areas, uncertainty remained until official confirmation.
Being smaller and shorter-lived does not make it harmless. Meteored warns that its winds can lift debris, bring down branches and damage roofs or lightweight structures, especially in populated areas.
At the Alameda terminal, damage was concentrated on the polycarbonate roofing of a metal structure between eight and ten meters tall, with no similar damage to nearby facilities. Trees and branches fell on San José and Plaza Estrella streets, and some roofs were damaged. Witnesses reported gusts lasting at least ten minutes.
The Quinta Normal station recorded 12.2 millimeters of rain between 16:17 and 17:17, with a peak intensity equivalent to 72 millimeters per hour. The temperature fell by about 10 °C, a change the DMC considered consistent with the passage of a gust front.
The sources do not specify the likelihood of another gustnado forming during this Tuesday's frontal system. For now, the warning is based on the forecast of storms for the Metropolitan Region.
