Wednesday, September 4, 2013

9/4/2013 Rim Fire Extended Air Quality Report

Rim Fire, Air Quality Resource Advisor Report                       Wednesday, September 04, 2013
 Prepared by: Ron Sherron, Leland Tarnay, Sharon Grant, and Ryan Bauer
Key Points:
  • Fire has burned 237,341 acres and is 80% contained.  1,500 acres of growth occurred during the last operational period.
  • Weather conditions are expected to start drying and warming throughout the week.  24 hr trend shows temperatures up from yesterday and RH is expected to decrease by 5-8%.  Mostly sunny today with SE winds this morning switching to S before becoming SSW this afternoon. Progressively warmer and drier conditions with stronger inversions and poor overnight recoveries will lead to less than favorable smoke conditions into the weekend.
  • Divisions A,B,D, and E will continue patrolling. Division F finished firing the line; no aerial ignitions were done yesterday. With conditions getting warmer and drier the priority will be to strengthening fire lines by building depth along burned out lines in the northern portion of the fire (figure 1). The second priority is direct attack in Branch IV (figure 1).  Line was completed around the spot fire in Division S and looks good.

Figure 1 Rim fire operations map for 9/4/2013 with MODIS satellite heat detections from 07:30 today (orange dots represent activity within past 12-24 hrs, red dots represent activity within past 6-12 hours) showing location of the  firing and holding operations in the Clavey River drainage (#1) and direct attack taking place in Branch IV (#2).

Figure 2 Rim fire infrared perimeter from 9/3/2013 with MODIS satellite heat detection and visible satellite image from 19:30, 9/3/2013 showing location of fire highest fire activity and visible smoke plume

Figure3 Rim fire infrared perimeter from 9/3/2013 with MODIS satellite heat detection and visible satellite image from 08:30, 9/4/2013 with outline of visible smoke.

Satellite imagery from this morning shows the main body of smoke from the Rim Fire extending north over Pinecrest, Markleeville, Minden, and Carson City, (Figure 3). Air quality monitors in those locations reported impacts in the unhealthy range in Pinecrest, Markleeville, and Minden this morning. Bear Valley and Carson City saw slightly less impact but still reached the unhealthy for sensitive groups AQI range for the 3-hour average. Smoke just skirts the Lake Tahoe Basin and Reno/Sparks areas with slight impacts that did not exceed the good range (Figure 4). BlueSky model predictions were a little bit closer on this today, as the southerly influence in transport winds just east of the Sierra crest was not as strong. This morning’s smoke impacts in Minden and Carson City were closer to what was forecast.

Also shown in figure 3 is an area of smoke that settled into the central valley overnight due to the slightly stronger inversion. Impacts from this so far are only depicted in Tuolumne City data, and smoke was evident in Sonora this morning for the first time in several days.

Figure 4 3-hour average fine particulate (PM 2.5) concentration at eight (8) monitoring locations downwind of the Rim fire with associated Air Quality Index (AQI) health hazard ranges and adjectives. All data are preliminary and have not undergone quality assurance review.

The air quality monitor at the Drew Meadow ICP was moved to a location farther from vehicle and generator emission sources. It is back up and running with acceptable data as of 15:00 9/3/2013. Smoke impacts continue during the morning hours each day at both base camps with a steady decrease in severity over the past four days (Figure 5).

Figure 5 3-hour average fine particulate (PM 2.5) concentration in the Drew Meadow and Tuolumne City Incident Base Camps with associated AQI ranges and adjectives. All data are preliminary and have not undergone quality assurance review.

Figure 6 air quality monitoring sites in the Rim Fire area with Rim fire infrared perimeter from 20:18, 9/1/2013.

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
For Wed.
Sept. 4, 2013
Yesterday, Sept. 3, 2013
La Grange
Greeley Hill
El Portal
Yosemite Vly
Air quality is satisfactory and poses little or no health risk
La Grange
Yosemite Vly.
Tuol. Mdws
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.
Tuol. City



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.
S. Lk. Tahoe
Tuol. City

Bear Valley
Markleeville. Pinecrest
Carson City
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.
Bear Valley
Drew Mdw ICP
Very Unhealthy
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.

Wednesday, September 4, 2013
As predicted, this morning’s smoke impacts extended further down-drainage than in recent days past, as a result of a stronger inversion and nighttime easterly/down-drainage winds. Morning smoke was present in Sonora for the first time in several days, and Columbia showed slightly elevated PM levels, but Greeley Hill and La Grange were not impacted. Morning impacts were highest north of the fire area in Pinecrest, Bear Valley, Tuolumne City, Markleeville, South Lake Tahoe, Carson City, and Minden (Figure 4). Inversions will be a bit stronger and could persist a few hours later before breaking. Southwest winds will continue to clean out smoke basins by early afternoon and should keep areas south and southwest of the fire mostly smoke free today. Carson City and Gardnerville/Minden may again see similar impacts beginning in the nighttime and persisting into the following morning (Figure 7).

Figure 7 2 km BlueSky particle model prediction for 16:00 9/4/2013.
Figure 8 2 km BlueSky particle model prediction for 07:00 9/5/2013.

Thursday, September 5, 2013
Smoke impacts continue to follow the pattern of the past two days. There is some hint that early morning impacts could extend further south and west of the fire area than the two previous days, possibly impacting La Grange, Sonora, and Columbia (figure 8) although the model has lessened this impact from yesterday’s prediction. Inversions will still be fairly strong, probably persisting until just before noon. Southwest winds will continue their dominance, cleaning smoke out of the west slopes of the Sierras by early afternoon. The BlueSky model suggests a more westerly influence on the path of the smoke plume east of the Sierra crest in the afternoon hours than has been seen over the past two days (Figure 9).
Figure 9 2 km BlueSky particle model prediction for 16:00 9/5/2013.

Friday, September 6, 2013
Morning smoke impacts are forecast to reach farther south and west under a strong inversion. Mariposa, La Grange, Columbia, Pollock Pines, and possibly even Auburn could see morning smoke impacts for the first time in several days (Figure 10). This agrees with IMET predictions for a stronger thermal belt, allowing for more nighttime fire activity, and the presence of a strong inversion trapping smoke form that activity in the drainages and valley. Southwest winds will continue, possibly becoming west-southwest later in the day as the Pacific low moves onshore over Washington (Figure 11). Impacts to downwind communities will be similar to those seen Thursday, September 5th. The Yosemite region should remain smoke free through the day.
Figure 10 2km BlueSky particle model prediction for 07:00 9/6/2013.

Figure 11 2 km BlueSky particle model prediction for 16:00 9/6/2013.

Long-range outlook
By this weekend winds are predicted to shift to a light northwest flow sometime Saturday into early next week. This could return smoke to the Yosemite Valley depending on fire activity on the Rim incident. A very rough estimate of approximately 20,000 acres of unburned fuels remains within the current fire perimeter with the potential to continue burning over the next several days. Assuming further growth outside the current perimeter does not occur, this acreage represents the potential for continued emissions from the Rim Fire.                                                      


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