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Record 1,  Textual support,  English

Record number: 1, Textual support number: 1 CONT

Kelvin-Helmholtz wave clouds are formed when there are two parallel layers of air that are usually moving at different speeds and in opposite directions. The upper layer of air usually moves faster than the lower layer because there is less friction. In order for us to see this shear layer, there must be enough water vapor in the air for a cloud to form. Even if clouds are not present to reveal the shear layer, pilots need to be aware of invisible atmospheric phenomenon.... The Kelvin-Helmholtz wave cloud does not last very long because the upper layer of air is usually drier than the lower layer, which results in evaporation of the cloud.  3, record 1, English, - Kelvin%2DHelmholtz%20wave%20cloud

Record number: 1, Textual support number: 2 CONT

Cattails below and Kelvin-Helmholtz wave clouds above - the clouds are formed by wind shear and any planes flying nearby would likely feel a few moderate bumps of turbulence.  4, record 1, English, - Kelvin%2DHelmholtz%20wave%20cloud

Record number: 1, Textual support number: 3 CONT

Another "specialty" cloud is one that can develop due to Kelvin-Helmholtz (K-H) instability waves and subharmonic resonance with other waves in the atmosphere. This can result in an intertwined or spiral cloud pattern ... K-H clouds that form in early stages can resemble well-organized waves that appear to be breaking like ocean waves.  2, record 1, English, - Kelvin%2DHelmholtz%20wave%20cloud

Record 1,  Textual support,  French

Record number: 1, Textual support number: 1 OBS

[...] l'élément intéressant sur cette photo, c'est ce petit cortège de nuages «dédoublés» [...] La forme allongée et plus ou moins enroulée de leur sommet, telle de petites vagues déferlant, est la conséquence d'une différence importante de la force du vent entre deux altitudes très proches. Ainsi les têtes tendent à se détacher des bases, soufflées par un vent plus fort, tout en s'enroulant sur elles-mêmes. Ce phénomène [est] appelé ondes de Kelvin-Helmholtz [...]  2, record 1, French, - nuage%20form%C3%A9%20par%20l%27effet%20des%20ondes%20de%20Kelvin%2DHelmholtz

Record 1,  Textual support,  Spanish