Valid Wednesday September 23, 2020 through Thursday September 24, 2020

 

Valid Wednesday September 23, 2020 through Thursday September 24, 2020

 

This advisory is in effect through Thursday afternoon. South Coast AQMD will issue an update if additional information becomes available.

 

Two major local wildfires are affecting air quality in the region. The Bobcat Fire is burning north of Azusa, Duarte, Monrovia, and Arcadia in the Angeles National Forest.  As of 7:00 AM on Wednesday, the burn area was reported at 113,307 acres with 38% containment.  Current information on the Bobcat Fire can be found on the Incident Information System (InciWeb) at https://inciweb.nwcg.gov/incident/7152.

 

The El Dorado Fire is burning in the San Bernardino Mountains near Yucaipa in San Bernardino County.  As of 8:00 AM on Wednesday, the burn area was reported at 22,601 acres with 68% containment.  Current information on the El Dorado Fire can be found on InciWeb at https://inciweb.nwcg.gov/incident/7148/.

 

Past and Current Smoke Impacts

 

The Bobcat Fire is producing substantial amounts of smoke while the El Dorado Fire is producing light smoke on Wednesday morning based on satellite and webcam imagery. Smoke from the Bobcat Fire and the El Dorado Fire is being transported towards the northwest. Smoke from the southern extents of the Bobcat Fire was visible in the San Gabriel River valley this morning and was being transported southeast.

 

All South Coast AQMD continuous PM2.5 monitors recording 24-hour average concentrations were below federal air quality standards on Tuesday. Since Tuesday afternoon, monitors and low-cost sensors throughout the South Coast AQMD jurisdiction measured Air Quality Index (AQI) levels in the Good to Unhealthy for Sensitive Groups categories except the South Coast AQMD’s temporary monitor near Azusa, which measured AQI levels in the Unhealthy category on Wednesday morning.   Visit https://www.aqmd.gov/aqdata to view current air quality conditions.

 

In any area impacted by smoke:  If you smell smoke or see ash due to a wildfire, limit your exposure by remaining indoors with windows and doors closed or seeking alternate shelter, and avoiding vigorous physical activity. For more tips on protecting yourself during a wildfire, see South Coast AQMD’s Wildfire Smoke & Ash Health & Safety Tips page:  http://www.aqmd.gov/wildfire-health-info-smoke-tips

 

Forecasted Smoke and Ash Impacts

Areas in direct proximity to the Bobcat and El Dorado Fires will experience the highest AQI levels due to smoke impacts.  Smoke and ash impacts will be highly variable in both timing and location through Thursday.

 

Los Angeles County

 

• Wednesday afternoon: Winds will be from the southwest and west and push smoke from the Bobcat Fire to the northeast and east into the San Gabriel Mountains and then out of the South Coast Air Basin.
• Wednesday evening through Thursday morning: Winds will be from southwest and west and push smoke from the northern extents of the Bobcat Fire to the northeast and east. Winds will be light and variable over the southern extents of the Bobcat Fire and is predicted to move smoke to the south and southwest.  Smoke is likely to remain closer to the ground overnight which can increase ground-level particulate matter levels.
• Thursday afternoon: Winds are predicted to move smoke from the Bobcat Fire to the northeast into the mountains of Los Angeles and then out of the South Coast Air Basin.

 

San Bernardino County

 

• Wednesday afternoon: Winds will be from the southwest and west and will push smoke from the El Dorado Fire to the northeast and east into the San Bernardino Mountains.
• Wednesday evening through Thursday morning: Winds will be from the northwest and push smoke from the El Dorado Fire to the southeast into the eastern portions of the San Bernardino Mountains. The East San Bernardino Valley could see higher PM2.5 levels from the El Dorado Fire as smoke is likely to remain closer to the ground overnight.  The San Bernardino Mountains and western San Bernardino Valley could also see an increase in PM2.5 levels overnight due to smoke from the Bobcat Fire.
• Thursday afternoon: Winds are predicted to be from the southwest and west and push smoke from the El Dorado Fire to the northeast and east into the San Bernardino Mountains and out of the South Coast Air Basin.

 

Riverside County

 

• Wednesday afternoon: Winds will be from the south and southwest and push smoke from the El Dorado and Snow Fires to the north and northeast.
• Wednesday evening through Thursday morning: Winds will be from the northwest and push smoke from the El Dorado Fire to the southeast into the San Gorgonio Pass and Coachella Valley. Areas in direct proximity of the El Dorado Fire as well as the East San Bernardino Valley will likely see the highest particulate matter levels as smoke is likely to remain closer to the ground overnight.  The Eastern Riverside County could also see an increase in particulate matter levels overnight due to smoke transported from the Bobcat Fire.
• Thursday afternoon: Winds are predicted to shift and come from the south and west. This will move smoke to the north and east and out of the Coachella Valley.

 

Extended Outlook for All Fires: Smoke impacts in the South Coast Air Basin and Coachella Valley will likely continue until fire activity decreases for the Bobcat and El Dorado Fires. South Coast Air Quality Management District will continue to provide daily smoke advisory updates until air quality impacts from smoke subside.

 

In order to avoid increasing PM2.5 levels even further, South Coast AQMD recommends that the public avoid burning wood during periods of poor air quality.

 

Areas of direct impacts and poor air quality may include portions of Los Angeles, Riverside, and San Bernardino Counties in the South Coast AQMD jurisdiction. Unhealthy for Sensitive Groups or higher AQI levels due to PM2.5 concentrations are possible in areas of direct smoke impacts. Impacts will be highly variable throughout the day, impacting different parts of the region at different times.