Convection

I was roused this afternoon from a chapter on nutritional deficiencies and related pathologies in Baabaaraa Blaack's book on sheep wellbeing, "All About Ewe, From Flock to Fleece", when a quire of loose paper burst out onto the balcony on a gust of wind, Starlight Glimmer in hot pursuit. Somepony had left the front door open and a whirlwind of rising air was racing up the stairway again. I went down to close a few doors before this Treecastle sucked all of Ponyville clean of dust, dirt and anything that wasn't nailed down. Spike is going to be grumbling for a week.

Down in the entrance lobby I found Applejack and Rainbow Dash engaged in a lively game of Ring Fling, the castle doors wide open to let in the warm spring air. It was a close game and they hadn't noticed the dull roar of air rushing up the stairs at the far end of the lobby or the vortex of debris merrily sailing in past them. The satisfying crack of wood on wood of a well flung ring and keeping score had all their attention. That and the grit on the floor that was making rings grind to a halt well short of the goal. I shut the doors and gave them brooms.

This place was not made to stable a herd.