Redemoinho vs. remoinho vs. turbilhão vs. furacão
Although redemoinho, remoinho, turbilhão, and furacão can all be associated with the idea of a whirlwind, they describe phenomena of vastly different scales, intensities, and contexts, ranging from a small swirl of leaves to a massive, destructive storm.
Redemoinho
B2This word describes a small, localized whirlwind, typically of dust, leaves, sand, or a small swirl in water. Figuratively, it refers to a contained jumble of thoughts or a small, chaotic gathering of people. It is the most common term for a small-scale vortex.
Um grande redemoinho de folhas secas se formou no canto do jardim.
(A large whirlwind of dry leaves formed in the corner of the garden.)
O cavalo se assustou com o súbito redemoinho de poeira na estrada.
(The horse got scared by the sudden dust devil on the road.)
Minha mente estava um redemoinho de preocupações antes da prova.
(My mind was a whirlwind of worries before the test.)
Remoinho
C1This word is essentially a synonym for redemoinho and is perfectly interchangeable in most contexts, although redemoinho is often more frequently used in modern speech. It also refers to a small vortex of air, dust, or water.
Cuidado com o pequeno remoinho que se forma perto das pedras do rio.
(Be careful with the small whirlpool that forms near the river stones.)
Um remoinho de crianças curiosas se juntou ao redor do mágico.
(A swirl of curious children gathered around the magician.)
Gosto de ver o remoinho que a colher faz no café com leite.
(I like to see the swirl the spoon makes in the coffee with milk.)
Turbilhão
B2A turbilhão is a much larger, more intense, and chaotic vortex than a redemoinho. It implies significant force and turbulence. It is very commonly used in a figurative sense to describe an overwhelming and chaotic succession of events, emotions, or thoughts.
O navio foi pego por um violento turbilhão e quase afundou.
(The ship was caught by a violent maelstrom and almost sank.)
Após a notícia, ela se viu em um turbilhão de emoções contraditórias.
(After the news, she found herself in a whirlwind of contradictory emotions.)
A vida na cidade grande é um turbilhão constante de atividades e ruídos.
(Life in the big city is a constant whirlwind of activities and noises.)
Furacão
B1This is a specific meteorological term for a hurricane, which is a large-scale, powerful, and highly destructive tropical cyclone. It is not a generic whirlwind. Figuratively, it is used to describe a person, event, or force that is overwhelmingly powerful and often causes massive change or disruption.
O furacão chegou à costa com ventos de mais de 200 quilômetros por hora.
(The hurricane reached the coast with winds of over 200 kilometers per hour.)
A nova CEO entrou na empresa como um furacão, demitindo metade da equipe.
(The new CEO came into the company like a hurricane, firing half the team.)
A crise financeira foi um furacão que abalou a economia mundial.
(The financial crisis was a hurricane that shook the world economy.)
Summary
In essence, the difference is one of scale, intensity, and specificity. Redemoinho and remoinho refer to small, harmless swirls. Turbilhão describes a larger, more forceful and chaotic vortex, often used figuratively for overwhelming situations. Furacão is not a generic whirlwind but the specific meteorological term for a hurricane, a massive and destructive storm, used figuratively to denote immense, unstoppable force.