East Bay Red Flag Check
Show HN: I built a Red Flag Warning zone-check tool for the East Bay in 48h
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What is East Bay Red Flag Check?
East Bay Red Flag Check is a free, no-app-firewall tool that tells East Bay residents whether their address falls inside the National Weather Service (NWS) Red Flag Warning polygon (zone CAZ515) for the East Bay Hills. The tool was built in 48 hours during fire season to close a gap in existing alert systems, where many people received text alerts unnecessarily while some in the hills didn't realize how close they were to danger.
Key features include: yes/no verification if the NWS polygon covers your address, your Genasys evacuation zone identification, tonight's wind and humidity readings at your specific point, a plain-English action checklist for fire safety, per-school decision views for East Bay districts, and a one-tap iMessage buddy-check template to send to a hill-neighbor. The tool works entirely without installing an app — you just type your address and get instant results.
This tool is specifically for East Bay residents, particularly those in or near the East Bay Hills who need to know if they should prepare a go-bag during fire-weather nights. It's also useful for parents checking school district decisions during red flag events, and for people wanting to quickly verify if a friend or buddy in the hills is in the flagged zone.
The tool uses licensed public GitHub data and NWS warning polygon data. It provides location-specific fire weather information rather than generic regional alerts, making it more precise than standard text alert systems. The creator emphasizes that NWS Red Flag Warning polygons are advisory only — wind-driven fires routinely push past nominal polygons, so users should treat fire-season nights as fire-weather nights regardless of polygon status.
Important safety guidance from the tool: keep a go-bag ready during fire season, as wind-driven fires like the 1991 Oakland Hills fire, 2023 Lahaina fire, and 2025 Palisades fire have historically pushed past warning boundaries until they ran out of fuel or hit the ocean.
East Bay Red Flag Check pricing
Pricing model: Freemium
Free — the tool is completely free to use with no account required and no paid plans. Built as a public service during fire season.
East Bay Red Flag Check pros
- No app installation required — works entirely in browser
- Instant yes/no answer if NWS polygon covers your address
- Shows your specific Genasys evacuation zone
- Provides tonight's wind speed at your exact location
- Provides tonight's humidity at your exact location
- Includes plain-English action checklist for fire safety
- Per-school decision views for East Bay districts
- One-tap iMessage buddy-check template for hill-neighbors
- Built specifically for East Bay Hills (zone CAZ515)
- Free to use with no account required
- Can check if a friend/buddy is in flagged zone
- Optional friend address field for zone lookup
- Uses licensed public GitHub data source
- Created in 48 hours to address alert system gap
- More precise than generic regional text alerts
- Location-specific fire weather data
- School pickup decision information for parents
East Bay Red Flag Check cons
- Only covers East Bay Area, not other fire regions
- NWS polygons are advisory only, not actual fire boundaries
- Does not predict where fire will actually spread
- Wind-driven fires can push past polygon boundaries
- No mobile app available for offline use
- Requires internet connection to work
- Does not replace official evacuation orders
- Limited to NWS zone CAZ515 only
- No historical fire data or trends provided
- Does not include real-time fire camera feeds
Frequently asked questions about East Bay Red Flag Check
What does this tool do?
This tool tells you if your address in the Bay Area is inside the National Weather Service Red Flag Warning polygon for the East Bay Hills (zone CAZ515). It also shows your Genasys evacuation zone, tonight's wind and humidity at your point, provides a plain-English action checklist, shows per-school decisions for East Bay districts, and lets you send a one-tap iMessage buddy-check to a hill-neighbor.
Do I need to install an app?
No. Everything works without installing an app. You just type your address on the website and get instant results including whether you're in the flagged zone, your evacuation zone, and fire weather conditions.
Is this tool free?
Yes, the tool is completely free to use. There are no paid plans or subscription fees. It was built as a public service during fire season.
What area does this cover?
This tool specifically covers the East Bay Hills, which is NWS zone CAZ515 in the Bay Area. It does not cover other fire regions outside the East Bay.
Is the NWS Red Flag Warning polygon a fire boundary?
No. NWS Red Flag Warning polygons are advisory only, not boundaries that stop fire. Wind-driven fires like the 1991 Oakland Hills fire, 2023 Lahaina fire, and 2025 Palisades fire routinely push past nominal polygons until they run out of fuel or hit the ocean.
Should I prepare a go-bag even if I'm not in the polygon?
Yes. The tool recommends keeping a go-bag ready during fire season regardless of polygon status. Treat fire-season nights as fire-weather nights even if your address is not in the flagged zone, because wind-driven fires can push past polygon boundaries.
Can I check if my friend is in the flagged zone?
Yes. The Buddy check feature lets you enter your friend's name and optional address to check if they are in the flagged zone. You can then send them a one-tap iMessage buddy-check template.
What school information does this provide?
The tool provides per-school decision views for East Bay districts. You can pick a school from the dropdown and check that school to see decisions related to fire weather conditions for that specific school.
What fire weather data is shown?
The tool shows tonight's wind speed and humidity at your specific point/location. This location-specific data helps you understand the actual fire weather conditions at your address rather than generic regional information.
Where does this tool get its data from?
The tool uses licensed public GitHub data and NWS (National Weather Service) warning polygon data. The GitHub repository is publicly available at github.com/vedant-f-is-ma/redflag-check.