High Sierra Topix

i suppose smoke could be this localized in the sierra, but the windy forecast image below doesn’t give me great confidence in their prognostication. the n/s dividing line is roughly bubbs creek/roads end/180. this isn’t just one slide: the forecast is that north of bubbs will be good-ish while south will be totally socked in with smoke over most of the forecast window. someone with more knowledge than me could weigh in here, but this sure seems suspicious.

El Dorado NF is closed:

http://southtahoenow.com/story/08/18/20 ... -september

frozenintime wrote: ↑Wed Aug 18, 2021 9:06 am the forecast is that north of bubbs will be good-ish while south will be totally socked in with smoke over most of the forecast window. someone with more knowledge than me could weigh in here, but this sure seems suspicious.

It seems to me that they're over-estimating the smoke from the Walkers fire, to me anyways. The EPA forecast is the opposite, and currently there's clear air around Lake Sabrina/South Lake.

This is obviously a question of risk tolerance, so it'll be a personal decision for you. But for me, risking a 12 hr drive, even if it was smoky and I bailed, I'd think I could have a good time. Obviously if you're getting on a plane, or if its easy to reschedule days you take off work, this changes the risk calculation for you.

thanks for your thoughts. my group is in the bay. unless things radically change between now and tomorrow AM, we are going.

i mostly wanted to chime in on the confusion and guesswork inherent to planning trips in the 21st century given the relative newness and accuracy (or lack thereof) of our forecasting tools. we will be reaping what we've sown with fire suppression and climate change for a long time, and i'm sure those smoke forecasting tools will get better pretty quickly. but for now, it all feels pretty damn magic 8 ball-ish.

frozenintime wrote: ↑Wed Aug 18, 2021 12:36 pm i mostly wanted to chime in on the confusion and guesswork inherent to planning trips

Yeah, totally. I think this sort of exercise other people will find useful. You can throw out the websites to use, but reading other people discussing an actual example is probably helpful for some.

I have been watching Airnow closely, and I often see areas where they claim three or four layers of smoke intensity, but their PurpleAir monitors report low AQI. Near hotspots, they coincide, but in much larger areas there does not seem be much of a correspondence.

All that aside, the hard truth is that it is all wind dependent, and the wind can change within hours.

It certainly is useful to see that the area I thought was sufficiently southern and "safe" to take a chance on grew two new fires overnight.

I am not real clear on how AQI is calculated. I believe Purple Air AQI is of particles less than 2.5. These are particles that harm lungs. The AQI can be relatively low and the visual effect horrible, since the larger particles can cause more haze. Where the many components of air quality are shown separately, just adding them does not seem to equal reported AQI. Not sure if ozone is added. Purple Air is also "citizen's" reporting and very localized. If someone has a sensor in their back yard, it may be impacted by them BBQ'ing dinner! Not sure they even record ozone. And the overlying smoke map trends do not match individual sensor AQI's.

As more roads get closed across the Sierra here in northern CA, it may become harder to even get to the east side.

Saddens me that for all the talk about "protecting Lake Tahoe" from the Caldor Fire, Desolation Wilderness seems to be treated as a pawn in the big game. Wilderness has little "high dollar" value- sort if let it burn to provide a fire break for Tahoe. I would hope that this impression I get is not what is actually being done and Tahoe just gets more press space.