Before finally clearing up, it had been raining for days, nonstop. A lot of the time, the rain was heavy. And as a result, many areas had underwent significant localized flooding.
As Harry and Hannah were getting ready to go for a walk together, they knew that there was a chance that they were going to encounter some very large puddles on their trail. Fortunately, thanks to Harry, they would be prepared for it.
Well, they did. They encountered a puddle that went entirely across the path. It was also too deep to simply walk through, and they both knew that they would also not be able to jump over it.
"Uh-oh," Hannah said, concerned. "What do we do now?"
"Hold onto me. And hold on tight," Harry instructed. He then took out his wand and pointed it at a distant tree. "Carpe retractum!"
A brownish-yellow beam shot out of Harry's wand and wrapped around the target tree like a rope. Next thing Hannah knew, they zoomed right over the puddle, landing safely (and dryly) on the other side.
She smiled. "Wow."
Harry grinned back at her. "Pretty cool, eh?"
Hannah giggled and kissed Harry before the two of them continued onward.
AN: I got this idea off of the PS2 version of the video game for Prisoner of Azkaban, where Harry could learn a rope-conjuring spell called Carpe retractum.