They should have at least 3 years worth of bottled water down in their tunnels, so….
consider dehydration.
That's nice and all, but windy.com shows that it's forest fire pollutants, most visible on the map below when selecting sulfur dioxide, which comes from wildfire and biomass fires, red and orange are a common color seen from wildfires and volcanoes when the sulfur dioxide reacts to form sulfate aerosols.
also note - https://www.today.com/news/why-sky-orange-wildfires-smoke-rcna91577
https://www.nbcnews.com/id/wbna26529769
"two days ahead of schedule" was probably to mess up any prediction of what year it would be then.