I have a permit for Sunday, Sept 19 and am wondering what the opinion is on what becomes a no-go for the hike in terms of air quality. My thought is that if AirNow.gov is showing red (Unhealthy) along the route that its time to plan for next year. I worry about air quality conditions changing during the course of the 16 hour hike (how long it took me my first summit in 2019). Just interested in your thoughts. I saw Doug Sr. said it was rough at the portal on Wednesday I think.

Don't know what it is like now, but I was up a few years ago when it was very smoky in the valley and the air got progressively better as we went up. I would give it a shot and turn around whenever it seems necessary. $.02.

I went over Kearsarge pass a couple weeks ago and spent 9 days doing the ray lakes loop and the circle of solitude and had great views and was not effected by smoke.

Erin, I live on the NW shore of Lake Tahoe and while it hasn't been as bad here overall as it has been for South Lake Tahoe and that area, the smoke from the Caldor fire has had a significant effect at times. (During the worst of it, I remember seeing an AQI of 646 one evening.) I learned a couple of things from recent events: first, that the AQI is very much subject to change even during one day depending on wind direction and how much it's shifting or swirling. I'd wake up some mornings seeing (relatively) good numbers, but by the time I'd be getting ready for a hike, the AQI had worsened because the wind shifted and I'd have to reconsider my plans for the day. Just because you've been seeing bad AQIs doesn't mean it will stay that way. Where you want to hike in relation to current wildfires has a lot to do with what to expect in air quality, and looking at the forecast can help determine if the wind would be blowing smoke toward or away from you. The second thing I've learned is that the numbers on AirNow are a rolling average. I now use purpleair.com to check the AQI. PurpleAir is a network of private and public air quality sensors which are constantly updating every few minutes, so it's more realtime. Go to purple air.com, click on "View the map," and allow it to use your location. Then you can drag and zoom to look at readings in the area you're interested in. At the moment, I'm seeing AQI in the 170 range for Lone Pine... IDK that it would stop me from heading out and seeing how it goes. YMMV. Hope this helps.

The fires in SeKi are raging badly right now. I just checked the day's webcam batch of pictures here. Can't even see Mt Whitney all day!

I would sure cancel the trip.

Second this recommendation. Use PA check AQI, I try to avoid hikes longer than an hour at an AQI 140+ I've been reckless and persisted up to 200, but as years pass I take more of these threats seriously.

Now if I took every weather forecast seriously I would never hike in the Sierra. On days tickling the unhealthy AQI zones I bring an N95 when I hike, hope for the best but when it gets bad on these days during the smoke season I come ready to bail.

That's me though.