While at Apple Park this week for WWDC, I had the opportunity to sit down with two Swift Student Challenge Distinguished Winners to talk about their apps and what it’s like giving a surprise demo to Tim Cook and John Ternus.

Asul by Karen-Happuch P. Henneh

First, I chatted with Karen-Happuch P. Henneh, the developer behind an app called Asul. Asul is an offline flood navigation app that uses flood data and weather forecasts to guide people in making safer travel decisions.

Karen explained to me:

My app is called Asul, which means flowing water in my language. I’m from Ghana in West Africa. Anytime it rains, the streets get flooded. I even have videos from just Monday showing what the streets look like.