Hey HN. I'm a high schooler in Fremont, CA. Tuesday morning I got a county-wide AC Alert text telling everyone in Alameda County to prepare a go-bag for an East Bay Hills Red Flag Warning that starts tonight at 11 PM. The text went to ~half a million phones. The actual NWS warning polygon only covers East Bay Hills (NWS zone CAZ515). Most people who got the text don't need a go-bag tonight. Some in the hills don't realize how close they are. I built this in 48 hours to close that specific gap: type your address, get a yes/no on whether the NWS polygon covers it, your Genasys evacuation zone, tonight's wind + humidity at your point, a plain-English action checklist, a per-school decision view for East Bay districts, and a one-tap iMessage buddy-check template for a hill-neighbor at 10:30 PM.

Stack: TypeScript on Vercel edge functions, NWS api.weather.gov, US Census geocoder, Genasys Protect for evacuation zones. Free, no signup, no tracking, MIT licensed. Public REST API + OpenAPI 3.1 spec at https://redflag-check.info/docs. Source: https://github.com/vedant-f-is-ma/redflag-check.

Today an Oakland Firesafe Council director emailed me critiquing the "outside the polygon" framing as falsely reassuring — wind-driven fires don't respect polygons (1991 Oakland Hills, Lahaina, Palisades). I shipped a fix in an hour and the wording across every surface now reflects that. Open to any other critique.