The Rim fire west of Yosemite has created smoke and particulates blowing mostly in a northeast pattern from the fire. This data is compiled and presented as an Air Quality Index (AQI). (click to enlarge)
This graphic below shows the smoke pattern for the entire western California/Nevada area. It can be seen that the trend towards Reno is hitting them with continued smoke. The remote northeast/west area of Yosemite is unhealthy, but the main valley has been spared. Occasional wind changes have brought smoke into the valley, but generally it’s been clear.
Now look at this computer projection based on atmospheric conditions.
For the next couple of days, the trend continues a flow of unhealthy air towards the Reno area. Tuolumne Meadows and Yosemite Valley can be seen as clear. By weekend, the winds are expected to shift to blowing from the northwest which could bring particulates into the valley. Air quality is expected to remain in the good-to-moderate range.
As you can see Yosemite valley is in the green to moderate. Basically, if you have asthma, are very old, or have lung issues, consult your doctor. But if you are young, healthy and need to hike Half Dome before the cables come down Oct 14 – I’d say “The mountains are calling and YOU must go!” ! See you up there next week.
Unrelated thought worth quoting: “The mountains are calling and I must go” – John Muir
MrHalfDome™ – Rick Deutsch – www.HikeHalfDome.com