Air Quality Report Thursday, September 12, 2013
Rim Fire, Stanislaus National Forest
Yesterday, September 11, 2013
The Rim Fire burned approximately 250 acres, almost entirely within the containment lines. It is currently 255,560 acres. Smoke production is primarily the result of heavy fuels that can continue to burn for several days within the fire area. Cloud cover and higher humidity helped to moderate fire activity. Most areas saw improved air quality from the previous days.
Thursday, September 12, 2013
Light downslope winds and a moderate inversion caused smoke to drain down the Clavey and Tuolumne River Drainages. Smoke impacts in the communities of Pinecrest, Columbia, Groveland, Greeley Hill, La Grange, El Portal, and Mariposa will be about the same as yesterday reaching their highest intensity early in the day and improving by afternoon. With transport winds still fairly light smoke impacts will remain localized. Evening impacts can be expected again for Tuolumne Meadows and Yosemite Valley with northwest ridgetop winds forecast. Diurnal upslope/upcanyon flows will be the dominant winds. A slightly chance of thunderstorms over the Sierras again today could aid smoke dispersion some in the late afternoon. Easterly winds will remain fairly light again tonight keeping impacts localized and probably not extending into the San Joaquin Valley.
Friday, September 13, 2013
Similar morning impacts can be expected in areas where the inversion will cause smoke to settle. Transport winds may be a little lighter, taking longer to clear smoke from foothill communities. Afternoon thunderstorm chances are lower than for Thursday. Northwesterly ridgetop winds will continue to send smoke toward the Yosemite region, which is likely to settle in the Tuolumne Meadows and Yosemite Valley basins in the evening. Nighttime easterlies will strengthen a bit, possibly moving smoke a little further into the San Joaquin Valley.
Long term Outlook
Conditions remain very similar Saturday, but start to transition on Sunday into Monday as a low pressure trough moves through. Winds will become southwesterly and temperatures decrease probably beginning sometime Sunday and lasting into early next week. This should give the areas south and west of the fire some clean air, and depending on the amount of remaining emissions, could return some smoke to areas north and east of the fire.
Follow the links in the following table to view real-time air quality monitoring data for each site.
24-hour Avg PM2.5
3-hour Max PM2.5
Level of Health Concern
Actions to Protect Yourself
Sept 12, 2013
Yesterday, Sept. 11
S. Lk. Tahoe Carson City Mariposa
Air quality is satisfactory and poses little or no health risk
Air quality is acceptable for most. There may be moderate health concern for a small number of sensitive people.
Unusually sensitive people should consider reducing prolonged or heavy outdoor exertion.
Groveland Tuol. Mdws
Unhealthy for Sensitive Groups
Members of sensitive groups may experience health effects. The general public is not likely to be affected.
People with heart or lung disease, children and older adults should reduce prolonged or heavy outdoor exertion. Everyone else should limit prolonged or heavy exertion.
Drew Mdw ICP
Everyone may begin to experience more serious health effects.
The following groups should avoid all physical outdoor activity: People with heart or lung disease, children and older adults. Everyone else should avoid prolonged or heavy exertion.
Air Quality Index (AQI) ratings are derived based on the recommendations found in Wildfire Smoke: A Guide for Public Health Officials.
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