Guest Post by Washoe County Air Quality: Wildfire Smoke in Northern Nevada


Special thanks to Washoe County Air Quality for being our first Guest Post! Enjoy! - NWS Reno 
Wildfires happen in the Sierra Nevada every year. The intensity and frequency of wildfires has been exacerbated with the increasingly dry conditions during the exceptional drought period across California and Nevada. If you are not close enough to the fire to be concerned with life and property, the next concern is your health in relation to smoke from wildfire. Let's take a look back at how much fine particulates (PM2.5) found in smoke has impacted the Northern Nevada region. 

Here are the top three 24-hour average PM2.5 air quality indexes (AQIs) for downtown Reno (2000-2015): 
1. CA Wildfires 6/25/08 - AQI 182 Unhealthy
2. King Fire 9/18/14 - AQI 174 Unhealthy
3. Rim Fire 8/23/13 - AQI 169 Unhealthy
For all three wildfire events, Northern Nevada experienced several days to over a week of smoke impacts above the 24 hour average National Ambient Air Quality Standard of PM2.5 set by the Environmental Protection Agency (AQI≥101).


Although these three wildfire days were considered Unhealthy with AQIs above 151, there were several hours during each of these days in which the air quality was not so bad. Here is a graph of the hourly PM2.5 AQIs from AirNow during one and a half days of the King Fire and how quickly the air quality can change:






When the air quality is in the Unhealthy for Sensitive Groups range or higher due to wildfire smoke, Be Smoke Smart and take precautions such as:
  • checking local air quality forecast and current conditions on AirNow.gov or your local air district website 
  • staying indoors with the windows closed; if too warm go to evacuation center or away from the area 
  • running an air conditioner if you have one, but keeping the fresh-air intake closed and the filter clean 
  • reducing activity and staying hydrated 
  • keeping indoor air as clean as possible 
    • eliminate tobacco smoke 
    • don’t use candles 
    • don’t vacuum – (yes, I am giving you an excuse not to clean.) 
  • following the advice of your doctor 
  • not relying on dust masks 
  • evacuating or temporarily relocating if needed 
Thanks to the National Weather Service in Reno for being a partner in getting wildfire smoke information out to the public. For more information on local air quality for Washoe County, go to OurCleanAir.com.


Popular posts from this blog

NWS Wind Forecasts: AKA What's the Deal With Friction?

Image
We have had a number of comments on social media which mention much lower observed wind speeds locally than are in the forecast. Well, you are unlikely to know this (it is not exactly advertised!) but National Weather Service wind forecasts are for 10 meters, or almost 33 ft, above the ground. As we are about to explain, that makes all the difference in the wind between eye-level (~5-6 feet) and ~33 feet.  It is natural to wonder the purpose of a wind height forecast well above where you and I typically reside. The main reason for this is the complication in forecasting wind as one nears the ground due to frictional influence caused by the surface. Here is a diagram showing the concept of wind speeds change as one gets away from the ground.  As you can see above, there is a rapid speed reduction (gray dashed line) near the ground with a lesser change away from the surface. Note that the above diagram is generalized. How much reduction is realized depends on the nature of the surface wh
Read more

What is the Rain Shadow and What's Wind Gotta do With It?

Image
The dreaded rain shadow - something that those of us who live east of the Sierra crest are more than familiar with and hate to hear. So what is this rain shadow and why does it even exist? Lets start with the topography just to our west... The Sierra Nevada mountain range runs 400 miles from north-to-south and is approximately 70 miles wide. It includes the highest peak in the lower 48, Mt Whitney at 14,505 feet, and rises above 10,000 feet in many locations. Left: The Sierra Nevada Mountains highlighted in blue. Right: A relief map showing elevation (in meters) of the Sierra. The Sierra are a significant barrier for Pacific storms which typically move from west to east. The movement of air masses and associated weather cannot go through the mountains and is forced up and over the mountain range. As Pacific moisture is driven eastward by the wind, the air mass is lifted up and over the Sierra. Rising air will cool and once it reaches the point of saturation, condense into
Read more

Forecasting "Dry Microburst" Potential From Soundings and Observations

Image
Summer afternoons in the valleys of eastern California and western Nevada usually feature dry low level relative humidity. In certain cases where low levels are very dry (single digit relative humidities) and enough instability for showers and/or thunderstorms exists, there is the heightened possibility for severe (over 60 mph) outflow winds. Now, severe winds are possible from strong thunderstorms in many cases, even without very dry surface relative humidity. However, what makes very dry surface or low level conditions special is that severe outflow winds are possible even with w eak  convection such as light showers...or even just cumulus clouds! When severe winds are produced by convection with little or no rainfall reaching the ground, it is referred to as a "dry microburst". Microbursts can be of significant danger to aviation and, if they are strong enough, life and property. Before we move onto what conditions we look for to determine the threat for dry microbursts,
Read more