Rashi on Numbers 9:17/רש"י על במדבר ט׳:י״ז

1העלות הענן — Understand this as the Targum does: the departure (more lit., the raising itself). Similar is, (v. 21): תעלה הענן which means “when the cloud raised itself” (departed; in both cases the verbs are Niphal). It would not be correct to have written in these passages ולפי עֲלוֹת הענן and וְעָלָה הענן (the verbs in the Kal), because this would not be an expression denoting departure, but “springing forth” and “rising”, just as, (1 Kings 18:44): “Behold a little cloud as small as a man’s hand rises (עלה) from the sea."