Monday, September 12, 2016

Monday, September 12, 2016 - Yosemite National Park Prescribed Fire at Ahwahnee Meadow -- Smoke Effects Forecast #1

Yosemite National Park
Prepared: 9/12/16 Prepared by:  Jim McNitt, Air Resource Specialist

Overview: The 62 acre YV-22 Ahwahnee Meadow prescribed fire project, is located in Yosemite Valley on the north side of the Merced River, south of Ahwahnee Road, east of Yosemite Village, immediately west of The Majestic Yosemite Hotel, straddling Yosemite Loop Drive. The goal of this project is to safely reduce hazardous fuel loading in Yosemite Valley, while achieving both ecosystem management and restoration objectives. Smoke Synopsis: Smoke from wildfires continues to affect the park and campfire smoke has been elevating the level of observed particulate matter in Yosemite Valley at night. An approaching upper-level trough will improve dispersion conditions from fair to good during the day on Monday and will increase wind speeds starting Monday afternoon. Due to a nighttime temperature inversion smoke produced by the fire Monday morning will not mix well vertically until late morning when the inversion breaks down and the surface wind speed increases. During the afternoon the smoke will be transported to the northeast. Outlook: Expect smoke dispersion conditions tomorrow to be fair in the morning and good in the afternoon on Tuesday and fair on Wednesday. High pressure is expected to build back in and dispersion conditions will begin to deteriorate by Thursday.
Location
Yesterday
9/11/16
Observed*
Day 1
9/12/16 Forecasted
Day 2
9/13/16
Forecasted
Details for avoiding smoke during the worst hours of the day. The Day 2 forecast assumes that all ignitions are completed on Day 1.

Yosemite Village and the Yosemite Valley Elementary School
Good
Moderate
Moderate
People with heart or lung disease, children and older adults should reduce prolonged or heavy outdoor exertion during the morning. 

The Majestic Yosemite Valley Hotel
No air mintor located at this site
Unhealthy for Sensitive Groups
Moderate
People with heart or lung disease, children and older adults should stay in air conditioned vehicles or buildings if they are near Ahwahnee Meadow during ignition on Day 1  and reduce prolonged or heavy outdoor exertion during the morning on Day 2. The 1-hr values of PM2.5 will be highest during the day on Day 1 during ignition.

El Portal
Good
Good
Moderate


Disclaimer:  These predictions are based on anticipated weather and fire activity.  Air quality predictions reflect only fine particulate matter (PM2.5). If you experience health impacts from smoke, contact your health professional. *The Air Quality Index (AQI) values used to create the table are 24-hr averages (midnight-midnight local time) of data from automated instruments. The data have not been subjected to a quality assurance review.

AQI Category
(PM2.5 µg/m3)
Potential Health Impacts
Actions to Protect Yourself
Good (0-12)
Little or no health risk
None
Moderate (13-35)
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 – USG (36-55)
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.
Unhealthy (56-150)

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.
Very Unhealthy
(151-250)
Triggers a health alert, 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.
Hazardous (>250)
The entire population is even more likely to be affected by serious health effects.
The following groups should remain indoors and keep activity levels low: People with heart or lung disease; children and older adults. Everyone else should avoid prolonged or heavy exertion
Air Monitor Data    http://www.wildlandfiresmoke.net/monitoring                                  
California Smoke Blog            http://www.californiasmokeinfo.blogspot.com                   
Air Districts    http://www.arb.ca.gov/capcoa/roster.htm   AirNow (AQI forecasts and nowcasts)   https://www.airnow.gov

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