Create Tornado (Elemental Spell)

A 30-foot-diameter, 700-foot-tall dark grey cylinder of violently rotating air magically forms on a point you can see within 1 mile of you. The tornado lasts as long as you maintain concentration, for up to 10 minutes. Any creature but you that enters the tornado must succeed on a DC 18 Strength saving throw or be restrained by it. You can move the tornado up to 30 feet as an action, and creatures restrained by the tornado move with it. The tornado ends if you lose sight of it. A creature can use its action to free itself, by succeeding on a DC 20 Strength check. If the check succeeds, the creature is no longer restrained, and falls 10 x 1d10 ft to the ground below, taking fall damage. Creatures inside the tornado are hit by swirling debris and take 3d8 bludgeoning damage per round, and struggle to breathe. When the point where the tornado touches the ground contacts trees or houses, it can rip roofs and branches off.