John Mills is the CEO and co-founder of a nonprofit called Watch Duty. His problem is this: How do you build an app to warn people when they are in immediate danger from a natural disaster? Watch Duty has millions of users and played a key role in the Los Angeles fires of 2025. In the show, John talks about how he built his app with the help of an army of volunteers, and why the government hadn’t already built something like Watch Duty. In this episode, John explains: • Why one-quarter of Los Angeles residents downloaded Watch Duty during the 2025 fires • Why the all-clear message matters almost as much as the initial warning • How they are expanding into flood warnings • How to decode firefighter’s radio chatter, and his favorite bit of jargon Connect with us: • Follow Jacob Goldstein on LinkedIn • , X • and Instagram • Email us at problem@pushkin.fm • • Follow Pushkin on Instagram • , LinkedIn • or X • • Listen to Jacob’s other show, Business History • To listen to the show early and ad free, sign up for Pushkin+ See omnystudio.com/listener for privacy information.