Plateworks Ignition is a field calculator for wildland fire. It computes Probability of Ignition, fine fuel moisture, and relative humidity from the NWCG Incident Response Pocket Guide (IRPG, PMS 461) and the belt-weather-kit tables.
- Platform
- Web, and iPhone in beta
- Requires
- A current browser. iOS 17 or later for the beta
- Price
- Free
- Status
- Web app live. iOS beta on TestFlight
- Made by
- Badwater Guidance LLC
Open the web app at ignition.plateworks.org. It installs to your home screen and works with no signal. The iOS app is in beta on TestFlight. The macOS app is in development.
The chain
It walks Table A, the B, C and D corrections, and the PIG table, and shows every step.
Enter temperature, RH, month, time of day, aspect, slope, and elevation against the weather site. Reference fuel moisture, the correction, and fine fuel moisture stay on screen so you can check each one against your own pocket guide. Results update as you type. There's no calculate button.
It computes PIG for shaded and unshaded fuels at once, and reads out the IRPG fire-behavior interpretation in plain language. Nighttime fuel-moisture handling is built in.
The sling
Relative humidity from dry-bulb and wet-bulb, across every NWCG elevation band.
A sling psychrometer reading gives you dry-bulb and wet-bulb temperatures. The app turns them into relative humidity, dew point, and wet-bulb depression, with the Alaska thresholds where they apply. The RH feeds the ignition calculation without being typed a second time.
The line
Built for gloves and for dark.
The controls are large enough to hit with a gloved hand. A true-black night mode protects dark adaptation. Every IRPG table value is a cell-for-cell transcription, checked in three independent passes and guarded by tests. The web engine and the Swift core are held at parity by generated vectors on every change.
| Accuracy claim | Basis |
|---|---|
| Every IRPG table value is a cell-exact transcription, not a formula. | Three independent passes reconciled cell by cell, guarded by property tests. |
| Relative humidity matches the printed PMS 437 tables. | Validated cell by cell at 30 inHg and 27 inHg across RH 3 to 94 percent, dry bulb 40 to 80 F, dew point -21 to 66 F. Those cells are golden tests. |
What it does not do
Decision support only. It is not affiliated with or endorsed by the NWCG. Verify against your own IRPG and consult local experts. The app has no account, no tracking, and collects no data. See privacy.