This is not an official warning. It is a global model forecast with cells of about 25 km, at the centre of the fire: it cannot see valley winds or the winds the fire itself creates. The fan shows where the wind blows, not where the fire will spread. If in doubt, follow what the authorities say.
☎
Emergencies · United States
911
Emergency number and official warnings ›
Forecast: ECMWF IFS 0.25° (European Centre for Medium-Range Weather Forecasts), served by our own Open-Meteo instance; the chance of rain comes from the ECMWF ensemble. Variables: wind and gusts at 10 m, wind at 850 hPa, relative humidity and temperature at 2 m, rain. Open-Meteo.com (CC BY 4.0).
Fire: VIIRS (NASA FIRMS); hotspots from the last 24 h: VIIRS from NASA FIRMS. Boundaries: geoBoundaries/United States Census Bureau, MAF/TIGER Database (Public Domain).
How it is worked out: wind shift = a change of more than 60° in 6 h or less, with at least 15 km/h before and after; no overnight recovery = peak humidity between 8 pm and 8 am stays below 55 %; useful rain = 2 mm or more in 6 h. The fan opens 18° plus however much the wind varies within ±3 h and reaches 25 km beyond the edge of the fire: one model cell, not a rate of spread. Methodology ›