Wednesday, September 23, 2020

Smoky siege: A look back at the smoke storm of 2020

The record-shattering smoke storm of 2020 is now behind us. Rain clouds have replaced the choking fog of smoke that held Washington in a vice for more than a week, and the annual dread of late-summer wildfires appears to have eased. 

Before we get back to business as usual, however, we wanted to review what exactly happened in the first three weeks of September, what it did to all of us that were stuck breathing that toxic soup, and what we can learn from this smoke event to prepare us for future summers when the smoke returns.

Prelude

For most of the summer of 2020, the Pacific Northwest enjoyed a mild wildfire season. The major impacts to air quality were a few fast-burning range fires near Yakima and Mattawa.

In the late August and early September, increasingly hot and dry conditions set the stage for what was to come. As Labor Day weekend arrived, so did the fires. The tiny town of Malden near Pullman was nearly destroyed by a fast-moving blaze, and a 1-year-old child died as his parents fled the Cold Springs Fire outside of Omak. 

On Labor Day, Sept. 7, the typical onshore flow of wind and weather systems moving in from the ocean shifted as high pressure built up over the interior northwest and low pressure set up along the coast. Since winds blow from high pressure toward low pressure areas, they began to blow from the east and strengthened quickly. 

In Washington, winds up to 50 miles per hour pushed smoke from the fires to the east across the mountains and into the cities of the Puget Sound region. Ash fell around Seattle, and the air took on the smell of a campfire.


On Sept. 8, air quality declined to unhealthy levels in the Puget Sound region. South of Seattle, a brush fire leapt up in the Tacoma suburb of Bonney Lake, destroying two homes and forcing thousands of residents to evacuate.

The situation in Oregon was much more dire. Wildfires exploded in southern, central and northern Oregon, forced the evacuation of entire cities, ultimately burning up to the edges of the Portland suburbs as nearly a million acres of forest and hundreds of homes succumbed to the flames.

A “super massive” plume

Smoke from these fires settled off of the Oregon coast, where the cool waters finally calmed the winds. Over the week of Sept. 6, the smoke built up into a super-massive plume – a ghostly echo as large as the state that spawned it.


At the Washington Department of Ecology, smoke forecasters watched this plume build with unease. Off the coast, the choking cloud of smoke posed little danger to Washington communities, and lighter winds were forecast with the potential to blow the smoke north, skirting the Washington coast and heading into Canada.

If the typical onshore flow were to return, however, the smoke would circle around the Olympic Mountains and crash into Seattle, threatening more than 4 million people in the city’s metropolitan area.

On Thursday, Sept. 10, the hope that Washington would dodge the bullet faded. Winds shifted to southwest, pushing the smoke toward western Washington.

The heat from wildfires can drive smoke high into the atmosphere, where winds can pick that smoke up and drive it hundreds or thousands of miles. That wasn’t the case this time. Cooler temperatures the night of Sept. 10 allowed the smoke to mix down to ground level, and western Washington awoke on Friday, Sept. 11, to ashen skies.

The super massive plume continued to creep across Washington through the weekend, subjecting first central and then eastern Washington to the thick smoke. Had the smoke simply continued to blow eastward, however, it would have gradually cleared out and allowed air quality to recover.

That didn’t happen.

Forecasting smoke is not like conventional weather forecasting. Wildfires can grow suddenly, unleashing fresh torrents of smoke and ash. New fires can pop up, or firefighters can gain or lose ground on existing fires. Smoke rises and falls during the day, driven by wind and temperature changes.

Because of these complexities, the same sort of sophisticated computer model that confidently predicts rain a week ahead of time struggles to accurately forecast smoke more than a day or two out. Smoke forecasters use their personal expertise to try to out-guess the computer models, but they, too, are sometimes caught off guard as wind and weather combine to frustrate their expectations.

“What do you do when the atmosphere doesn’t deliver what you ordered?” asked Dr. Ranil Dhammapala, an atmospheric scientist and smoke forecaster with Ecology. “You try to diagnose the problem, take into consideration the lessons learned and issue an updated forecast.

“We look at multiple weather and smoke models, each with their own strengths and weaknesses,” Dhammapala said. “We also consider feedback from other forecasters, wildland fire managers and look at monitoring data continuously. Forecasts are constantly recalibrated as new information becomes available.”

The night of Sunday, Sept. 13, such a recalibration proved necessary. The wind working to clear the plume faltered. A new, weak front was forecast to continue the clear-out, but those winds instead sailed mostly overhead.

Why? With no wind and a thick blanket of smoke over the entire state, little sunlight reached the surface, meaning there was none of the usual daytime warming that produces evening breezes. Just as it does during wintertime temperature inversions, the smoke settled in the valleys and basins of Washington, forcing millions of residents to shelter inside.

A dark cloud

As that smoke settled, air quality grew worse and worse.

Between Saturday, Sept. 12 and Thursday, Sept. 17, every single air quality monitor in Washington state recorded levels of particulate pollution above the federal 24-hour standard.


Particulate pollution, especially the tiny particles known as PM2.5, pose a serious threat to human health. PM2.5 particles are 2.5 micrometers or smaller in size - so small that our bodies’ natural defenses don’t work against them. They lodge deep in our lungs and even get into our bloodstreams.

Short-term exposures to PM2.5 can irritate your eyes and throat, produce headaches, and leave you short of breath. For people who already suffer from a respiratory illness or heart disease, the effects are worse, and can be life-threatening.

“It’s very clear from research done here in Washington and in other places that more and more of the population suffers certain health problems when there’s a lot of wildfire smoke,” said Dr. Matt Kadlec, Ecology’s smoke toxicologist. “It’s common for people to have eye and respiratory tract irritation; stress; headaches; shortness of breath; and, among those who already have asthma, worsened symptoms. As smoke levels increase and last longer, respiratory and cardiovascular health risks increase, resulting in greater incidences of emergency department visits, hospital admissions, and even deaths.”

Washington is no stranger to wildfire smoke. The Carlton Complex Fire in 2014 burned more than a quarter-million acres and destroyed more than 350 homes in the Methow Valley. In 2017 and again in 2018, huge wildfires in British Columbia sent smoke southward, blanketing much of the state for weeks.

As bad as these smoke events were, they could not compare to September 2020.

Ecology scientist Dr. Beth Friedman looked at historical records going back to when the agency began tracking PM2.5 levels in the early 2000s. She found that more Washington cities were exposed to hazardous air quality – the highest category for air pollution – for longer than during any previous smoke event.

“This smoke event marks the most days statewide PM2.5 monitoring sites have recorded hazardous air quality going back to 2000, and the majority of the state experienced at least five consecutive days of very unhealthy or hazardous air quality,” Friedman said.


As the smoke lingered, hundreds of questions poured in to the Washington Smoke Information blog, where Dhammapala and fellow smoke forecaster Farren Herron-Thorpe tried to provide updated forecasts, explanations, and advice. More than 2.5 million people visited the smoke blog over the week, while another 2.6 million looked to Ecology’s air quality monitoring map for the latest conditions.

Light winds in the middle of the week momentarily cleared the smoke from a few spots on the coast, but then also brought a second wave of smoke from Oregon fires. 

When would it end?

Hope on the horizon

After the dashed hope of relief on Sept. 13, commenters on the smoke blog and social media were skeptical of forecasts. To Dhammapala, Herron-Thorpe and other forecasters around the state, however, the signs for optimism were clear: Another weather system was due to arrive on the Washington coast Thursday, Sept. 17. The front would bring rain and gradually push the smoke northeast.

This time, the front arrived right on schedule. Air quality monitoring stations on the Washington coast showed good air quality by late morning Thursday. Further inland, though, air quality remained in the very unhealthy category in the Puget Sound region, and hazardous in most of Eastern Washington.

Slowly, slowly, that began to change. Friday afternoon saw heavier rains and scattered thundershowers. All over western Washington, people’s moods seemed to lighten as the smoke lifted, even though it hovered around the unhealthy range much of the day.

By Saturday, western Washington was clear – air quality monitors showed nearly all green on the map. Eastern Washington and Spokane had to wait another day for relief as the storm swept the smoke away.

And, on Sept. 21, it was all just a memory.



The new normal?

Are smoke events like this the “new normal”? Do we need to prepare for weeks stuck inside every summer from now on? Is there anything we can do to prevent that?

The Magic 8-ball tells us that the future is uncertain. Climate researchers predict that the number of acres burned each year in the west will continue to rise, as warmer winters eat away at mountain snowpack, and hotter summers dry foliage more quickly, setting the stage for wildfire.

Those long-term trends don’t tell us about any particular fire season, though – after major smoke events in 2017 and 2018, 2019 was a very mild year. And the wildfire season of 2020 was unexceptional for most of the summer. Until our luck ran out.

Even when fires race across the west, that doesn’t mean the more heavily populated regions will be hit by smoke. The sequence of events chronicled above shows that several factors have to come together in the right sequence for smoke events of this magnitude. In 2020, strong east winds allowed a super-massive plume of smoke to accumulate offshore, but had the wind shift been followed by stronger on-shore flows, that reservoir would have quickly drained.

Still, three of the past four years have seen days or weeks of unhealthy air in Seattle, Tacoma and Vancouver. Clearly, everyone in Washington needs to be prepared to protect themselves and their families when smoke arrives.

N95 masks – the most effective portable protection against PM2.5 – were hard to come by in this pandemic year. The simple cloth masks most Washingtonians wear to reduce the spread of the coronavirus provide little protection against the tiny particles.

Staying inside with the doors and windows closed is the best advice to reduce smoke exposure, but that’s a tall order when hazardous air quality goes on day after day. Making sure your air conditioner – for those fortunate enough to have it – or furnace is set to recirculate helps to keep smoke outside. A clean filter with a MERV rating above 11 will capture some of the particles that do get in, and can significantly improve indoor air quality as the air recirculates.

Tens of thousands of people watched Ecology’s “how-to” video showing a simple trick to strap a furnace filter to a box fan, offering an inexpensive way to create a clean air shelter.

2020 was a record-setter. Whether it is a harbinger of the future or an exceptional event remains to be seen. What 2020 has taught us, though, should be a call to action for everyone in Washington to be prepared for smoky skies and toxic air.

Monday, September 21, 2020

Phew, glad we're done with that. Now what's next?

No doubt everyone breathed easy yesterday when air quality in the whole state returned to Good. How long will it stay that way?

The map of monitors above shows Moderate or Unhealthy for Sensitive Groups air at several locations in Clark, Klickitat and southern Yakima counties. These are due to smoldering fires nearby. Even though fires are not puffing smoke like they were, low- buoyancy plumes are still draining some smoke into nearby cities. 

These kind of relatively low grade and relatively localized impacts will continue on and off through late Tuesday. "Low grade" compared to last week, that is. A weak system tonight won't help a whole lot but a strong, wet front early Wednesday will show the smoke who's boss and knock back the fires. Impressive 24-hour total precipitation ending 5PM Wednesday, as per the average of all ensemble models at UW.

Two weaker storm systems are expected Thursday and Friday, bringing more good news to smoke- weary Washingtonians. However calmer, dryer conditions under high pressure are possible Sunday onward so lets not pop the champagne cork yet. 

Friday, September 18, 2020

Slow improvement still happening, plus more data showing WA population exposed to smoke

Forecast update

The Olympic Peninsula has pretty much cleared out now, and several Puget Sound area sites are trending downward. Rain is helping a bit, but the weakening inversion is helping most. Still on track to see mostly Good to Moderate air in western WA by tomorrow

Just for kicks, take a look at how some sites in the Olympic Peninsula responded yesterday when a low pressure system offshore initially helped ventilate the area and then dragged in smoke from Oregon fires. Who said smoke dynamics aren't complex!


Most monitors in eastern WA have been pretty static today (read: Unhealthy to Very Unhealthy air) but cross Cascade winds are starting to pick up and will eventually make their way into the Columbia Basin overnight. Eastern WA will start seeing seeing improvements on Saturday, reaching Good to Moderate by Sunday

We're nearly theredone for now. Don't be fatigued with the health precautions.

FYI, Ecology's air monitor in Yakima will be taken offline later today due to renovations happening at the host facility. But our staff proactively installed a temporary monitor in Union Gap, so there is no gap (no pun intended, honest!) in data coverage. Data should start appearing on the above map very soon. 

Population exposed to smoke (written by Ecology's Andrew Wineke)

As an agency dedicated to protecting air quality in our state, we’ve been trying to wrap our minds around not just what the numbers are this hour, but what the longer impacts of this kind of smoke storm may be. 

As we’ve moved from one record-poor air quality day to the next, we’ve shared some charts and analyses as we work through those questions. One important takeaway is that more Washington communities have been exposed to more hazardous levels of particulate pollution than we’ve ever seen since we began monitoring for PM2.5 (the most concerning type of particulate pollution found in wildfire smoke) back in the early 2000s.

Geographic extent is just one way to look at it, though. Sometimes, we have quite serious wildfires that don’t affect many people – either because of helpful weather patterns that blow the smoke away, or simply because they are burning in thinly populated regions.

Ecology researcher Beth Friedman looked at how many Washingtonians have been exposed to extended periods of unhealthy air, compared to other recent smoke events. Looking at the smoke exposures this way helps us contrast this year’s smoke storm with other major events like 2018, where smoke from Canadian wildfires bathed much of our state with a longer period of less-intense air pollution. 

So how does 2020 measure up when we account for populations in smoke- impacted areas? It may not surprise you that 2020 is a stinker: The number of people exposed to very unhealthy or worse air quality for a week or more is practically off the charts compared to 2018, 2017, or 2015. 

Or if you want to include the Unhealthy category in the comparison:

Clearly, this has been an incredibly bad week for Washington’s biggest cities – and it hasn’t been a walk in the park for our less populated areas, either. 

Thursday, September 17, 2020

The worst is behind us but it ain't over yet

So when will it be over?

Western WA: Early Saturday

Eastern WA: Saturday night

Why so long?

Western WA: Encouraging reductions at Olympic Peninsula monitors today and smaller improvements since yesterday in the Puget Sound lowlands. But strong winds off the Pacific are MIA so we have take what the lighter, shifty winds with a little rain (minions!) dish out. These minions are bringing disorganized, mixed results. Some smoke from Oregon fires are now being transported to western WA due to a wind shift, and even though a lot of that smoke is still aloft, it delays the already slow scrubbing process. Expecting Good to Moderate air in much of western WA by Saturday. 

However Clark county and the Columbia River Gorge might continue to see Very Unhealthy air through tomorrow at least because of the proximity to fires, and their relief will be later on Saturday.

Eastern WA: The last 3 runs of the more pessimistic models have continued to show good ventilation across the Columbia Basin on Saturday, so there is good confidence this wont be a busted forecast. This will not immediately erode away all the smoke stuck in valleys, so it needs some time to do it's thing. By Sunday morning most of the air should be Good to Moderate, except very close to fires. 

So how bad did it get?

Some of our readers asked to see a comparison of the # of successive days we were exposed to Very Unhealthy or Hazardous air. Dr Beth Friedman constructed the following plot to answer this question. 

All of 2020's days were from the last week or so. Sadly this wasn't the worst run of bad air for our friends in Chelan and Okanogan counties. 

Note: Monitors did not operate during all of the last 3 years are in the following 3 counties, and they are not included in the above plot. Their stretch of bad days was:

County

2017

2018

2019

Kittitas

3

No data

5

Klickitat

No data

No data

7

Thurston

No data

2

6

 But it is nearly over now and we don't see an immediate return to terrible air next week, so hang in there Washington!

P.S. Don't throw open your windows to air out the house the moment air quality improves. With these minions around, it is best to wait a few hours to be sure there is a sustained improvement. 

Understanding your Air Quality numbers

 As our coastal sites turn green this morning and we start to see hope for clean air for the rest of us later today and tomorrow, I thought I’d take a minute to clarify some common misconceptions regarding air quality numbers, where they come from and what they mean to you.  The two indices, Air Quality Index (AQI) vs. Washington Air Quality Advisory (WAQA), have created a lot of confusion.

Both AQI and WAQA are a unitless index calculated from a given concentration of air pollution. There are several different measured pollutants that affect air quality: PM2.5, ozone, NOx, CO, and SO2. PM2.5 is the most commonly measured and generally the one of most concern in Washington state, especially during wildfire smoke episodes. Although all these pollutants can affect AQI and WAQA values, I’m only going to focus on PM2.5 in this post.

State and Federal government run air quality maps (https://airnow.gov and https://enviwa.ecology.wa.gov/home/map) use the same air quality monitors and data to determine air quality in your area, but they use a different index to represent what that air quality means for your health.


So, why are there two different indices?  Although we assign breakpoints to the different categories, air quality is a spectrum. Every person will be affected by poor air quality differently.  These are general guidelines and the breakpoints are based on statistical assessments of how large numbers of people respond to varying levels of poor air quality. EPA studies have assigned risk at a certain point, while Washington state toxicology research found more protective levels would better serve our community. Looking at the breakpoints in this table, a PM2.5 concentration equal to 50 ug/m3 is considered unhealthy by WAQA standards, but unhealthy for sensitive groups when using the AQI scale. You are not a statistic and may be adversely affected at moderate levels, or perhaps you can go hiking without difficulty when conditions are unhealthy for sensitive groups.  For individual health concerns, your best bet is to consult your doctor.

AQI and WAQA health risk categories are based on a 24-hour exposure. The number you see on the map is updated hourly and represents the previous hourly average weighted by the air quality observed over several hours before. For example, if the air quality is green all morning and a nearby building catches on fire, smoke may affect the monitor for one or two hours at unhealthy (red) levels, before returning to green. The monitor may only show unhealthy for sensitive groups (orange) during those two hours since the exposure time was so short. As we observed at the beginning of this smoke event, heavy smoke rolled into some areas very quickly and air quality went from good to hazardous in 30 minutes. The map will not update that value until the hour of data collection is complete and may take another hour or two to catch up to instantaneous air quality. Both airnow and the state maps have the option to look at the actual hourly PM2.5 concentration from the previous hour. Those numbers will be the same on both maps.

The second question we often get is “who is more trustworthy? My air quality app, a third-party air quality reporting site, airnow, or the state air quality map”? It is important to understand all these sites are using the same data, if they are using actual air quality measurements. We don’t often know how third-party apps and websites calculate the AQI or interpret our data. In that sense, we consider EPA and the state map to be the gold standard as we are directly involved in collecting the data, making sure it’s valid, and reporting the concentrations.

 

Wednesday, September 16, 2020

Since this is the era of big data, lets compare our plight with those from far and wide

There are claims that we've been exposed to the worst air in the world. True? Fair comparison? Let's investigate that without belittling the terrible air quality conditions we've all had to endure for at least a week now.  

Here's a map of global air quality right now. It uses all available measurements worldwide and uses machine learning methods for spatially interpolation. US west coast is in baaad shape. Worst ranked cities right now are all in our neck of the woods. 


But to do a proper apples-to-apples comparison, we should compare our air during our "bad" season with the "bad" seasons in other places, not our bad against their better times. So lets leverage data from the US State Department's (DoS) air quality monitors around the world. These are easily obtained from one place and have a pretty good quality control regime. 

I've pooled PM2.5 data from the ten highest embassies which recorded data for at least two years anywhere between 2012- 2019. These are: New Delhi & Kolkata (India), Dhaka (Bangladesh), Ulaanbaatar (Mongolia), Kampala (Uganda), Kathmandu (Nepal), Jakarta (Indonesia), Chengdu & Shenyang (China), and Manama (Bahrain). You can see more details about their air quality here. "Normal" conditions were defined as the range between monthly lower and upper quartiles, since the median passes right in the middle of it. This is also known as the interquartile range, or IQR.

The above figure shows how air quality in Seattle, Spokane, Vancouver, Omak and Yakima have varied from 1 Jan- 15 Sept 2020, against the backdrop of IQRs at ten embassies. As can be seen, the overseas cities experience terribly compromised air quality primarily in the winter months. Right now is their "better" season. Even though we spiked right to the top of the AQI chart this week, bear in mind that:

  • All these overseas locations see concentrations that are higher than their own IQRs 25% of the time. Or put another way, they record even higher concentrations for 3 months of the year.
  • Our air will not remain this bad for several months. Most WA sites have experienced some improvement already and we're still on track to clear out in the Friday- Saturday timeframe. 
  • In spite of our wintertime temperature inversions and woodsmoke concerns, we're still in far better shape at that time of year.

Moral of the story: yes its bad here now. Many others have it worse for much longer. Folks who live in these environments and our diplomats serving there can offer us some coping tips.