Rim Fire, Air Quality Resource Advisor Report Monday, September 9, 2013
Prepared by: Ryan Bauer, Leland Tarnay, and Sharon Grant
- The fire size is currently 254,685 acres and is 80% contained. About 1,700 acres of growth occurred yesterday. Approximately 1,400 acres of those acres burned in green islands within the fire perimeter. Roughly 5,000 acres of green islands remain within the perimeter. Approximately 300 acres of new growth occurred on the eastern portion of the fire.
- High temperatures and very dry conditions will continue through today. Instability remains high along with the potential for plume dominated fire behavior and spotting. The good news is humidity will increase slightly and temperatures decrease slightly today and tomorrow. Slope and drainage winds will be fairly light except where they align with west facing drainages in the afternoon. Isolated thunderstorms are possible along the Sierra crest. Weaker easterly winds will return tonight.
- Interior islands continue to burn in the Clavey drainage although firing operations are finished in the northern portion of the fire. Westerly winds continue to help hold firelines in the north and reduce the threaat of spotting. Crews continue to hold direct firelines in Division Z north and northeast of Cherry Lake. Two Wildfire Use Modules continue working the eastern side of the fire to check the fires spread in several timber stringers that run up into the rocks. Several spot fires were contained and mop-up continues in Division P as unburned islands of fuel continue to burn in the fires interior. All other Divisions continue mop-up, patrol, and suppression damage repair.
From yesterday’s analysis of areas of unburned fuels within the fire perimeter that have the potential for continued emissions, approximately 6,500 acres were identified. As of this morning roughly 1,400 of those acres have burned (Figure 2). An additional 380 acres of growth occurred within the timber stringers east of the fire that terminate in the rocky peaks of the Yosemite Wilderness. Up to another 1,000 acres of spread is possible over the next several days in that area if all suppression efforts are unsuccessful.
Satellite imagery from this morning shows dense smoke from the Rim Fire extending down the Clavey and Tuolumne River drainages, and in a light band along the Sierra foothills from about Angels Camp south where it joins smoke from the Angora fire around Springville (Figure 3). Air quality monitors in Greeley Hill, La Grange, El Portal, and Columbia were not showing much impact this morning due to the smoke being held aloft, but some mix-down is expected to reduce air quality in those areas as the inversion breaks later this morning. Groveland and Tuolumne City measured higher impacts this morning in the unhealthy and unhealthy for sensitive groups ranges, respectively (Figure 4), but all areas generally saw much lower impacts than on previous days. Communities north and east of the fire remained in the good range this morning.
Air quality monitoring continues at the two incident base camps. Smoke impacts reached the very unhealthy range in Tuolumne City yesterday, but today there is a break from the smoke as a result of the change in transport winds. The same wind change increased impacts for the Drew Meadows Camp (Figure 4).
Table 1 selected air quality monitor data and corresponding AQI rating, meanings, and recommendations with forecast levels for today. Data are preliminary and have not undergone quality assurance review.
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. 10, 2013
Yesterday, Sept. 9, 2013
S. Lk. Tahoe Carson City Minden
Air quality is satisfactory and poses little or no health risk
S. Lk. Tahoe
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.
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.
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.
Drew Mdw ICP
Triggers a health alert, meaning everyone may experience more serious health effects
Everyone should avoid any outdoor exertion; people with respiratory or heart disease, the elderly and children should remain indoors.
Air Quality Index (AQI) ratings are derived based on the recommendations found in Wildfire Smoke: A Guide for Public Health Officials.
Tuesday, September 10, 2013
Wednesday, September 11, 2013
Morning impacts will be similar to the past two days for the Yosemite and San Joaquin Valleys, as well as extending further north into the Sacramento Valley and foothills as well (Figure 9). Westerly transport winds may increase a little, clearing smoke a little better from the central valley and foothills. Markleeville, Bear Valley, and Pinecrest, could begin to see light smoke impacts once again (Figure 10). Predicted smoke impacts in figure 10 north of the white line are associated with erroneous emissions from the American Fire and are not likely to occur. Nighttime easterlies will be weaker, with moderate inversions, causing slightly less impact to the San Joaquin, but similar impacts to the Yosemite region and foothills.
Thursday, September 12, 2013
Conditions remain similar Thursday, with morning impacts maybe a bit less in the San Joaquin Valley, as nighttime downslope winds are predicted to be lighter. Daytime transport winds remain westerly and strengthen a bit, providing a little better clearing west of the fire. The model indicates light impacts possible in the Owens Valley in the morning (Figure 11).
Long Term Forecast:
By the weekend high pressure rebounds, daytime transport winds weaken, and nighttime easterlies once again strengthen, but reduced smoke production should moderate air quality impacts from the Rim fire by then.