The piece
Four Lento bars first present the theme, in a single voice and then harmonised, like an announcement. Then the Allegro con brio, risoluto, hands it to the left hand in march-like chords, while the right hand pours down the keyboard in cascades of sixteenth notes. The “Winter Wind” nickname is not Chopin's. The penultimate étude of Op. 25, it follows here the first Paris edition by Henry Lemoine (1837).
The right hand sustains nearly fourteen attacks per second: each descent starts from a point of support and unrolls through a rotation of the wrist, with the fingers staying close to the keys. Do not chase speed before you have found this motion, or the hand will lock. The left hand must mark the theme in clear chords without covering the right; some stretches reach 17 semitones. The 40 repeated notes belong to the rhythm of the theme and need to stay sharply cut. Practise hands separately, then combine them using the left as your reference: it tells you where the beats fall while the right fills the space.