Forest Fire
Atmosphere Daily Earth Science Environment Repost

Living with Fire and Smoke

Oregon Burns

We are hunkered down on the outskirts of Portland’s metropolitan area, just west of the Willamette River. Facemasks (N95) hang near the garage door, ready for taking the dog out several times a day to pee. The virus is a secondary thought, and now keeping smoke out of our lungs is a day-long task. Each room in the house reveals a slight tinge of smoke in the air. South of us, and slightly east of Salem, the Beachie Creek and Riverside fires are dangerously close to merging. The saying in Portland is,” no one goes on vacation from July through September, because there is no better place to be” — clearly not true this year. What went wrong?

It’s a legitimate question, but it would be easier to answer if we flipped it over and asked, “what went right?” — Nothing. Unsurprisingly the story starts with heat. One allure of Pacific Northwest summers is a dry season between July and October. Most years, residents are guaranteed long strings of warm sunny-seventy days, cool evenings in the back garden, and weekend hikes in the mountains. But dry seasons on the West Coast have trended toward starting earlier, ending later, and having hotter average temperatures. Longer, hotter, and dryer conditions prime the forests for burning.

After dry heat, the second component of a raging wildfire is strong winds to fan the flames and spread destruction. Mother nature obliged by sending winter strength winds in September. Typically high winds from the east and northeast descend on Portland in the dead of winter, spilling frigid air over the Cascades and through the Columbia River gorge. But this September, winds with gusts of up to 65 mph swept in from the east, carrying hot, dry air from the high deserts east of the Cascades. This freak windstorm was the first harbinger of oncoming destruction as it rolled in on a Monday afternoon.

Ignition

Ignition technically occurred in August when summer lightning storms passed over the state setting off numerous small fires. The Beachie Creek fire was only 469 acres before the winds arrived. Overnight the fire exploded, encompassing 131,000 acres by the next day. Fire and wind beget more flames, then burning debris, or maybe more lightning, sparked additional fires. Over a million acres across the state have burned, and a half million people are under evacuation warnings.

My back deck is on a hill about 700 feet above sea level. From Monday afternoon to Wednesday morning, the winds, stoking an inferno in mountains to the south, kept the smoke at bay. I was at the proverbial intersection of the yin and yang with dark reddish-black skies to the south and crystal-clear blue to the north. We hovered in this borderline condition until Wednesday when the wind died back, removing the invisible smoke containment forcefield. Daylight turned a sickly yellow, and a fog of smoke enveloped our neighborhood. From there, the smoke poured into Portland, giving it the dubious distinction of having the worst air quality in the world — a rating of 206 (Very Unhealthy, signifying that everyone may experience more serious health effects).

I was feeling blue about my situation until watching the Thursday evening news. Tens of thousands of people were fleeing their homes just miles from our house. Pictures of affected communities popped on the screen, showing neighborhoods burned to the ground, leaving the residents with smoking ash instead of homes. The slightly smokey smell of our house didn’t seem too bad anymore.

Few comments, if any, appeared from our national leaders, but several conservative relatives reminded us we should have been raking up the forest floor. Yes, this is clearly the problem, I muttered, not climate change and past forest management practices. Where was Donald and his rake when you needed him?

PyroCbs

Forest fires are wild and sometimes unpredictable events. Major wildfires create their own local weather systems. One evening, fascinating time-lapse pictures showed billowing and churning clouds far above the fires at the top of the cloud layer. This intense heat creates pyrocumulonimbus clouds or pyroCbs. Cb is an abbreviation for cumulonimbus clouds, hence the term pyroCbs (fire-clouds).

The basic physics of convection and updrafts apply to wildfires. Fire heats the air, making it less dense than the surrounding atmosphere, and the hot air rises. Then, the rising air creates an atmospheric void at the earth’s surface, causing winds to form as fresher air moves in to fill the void. If a fire is particularly intense, air spirals in from all directions creating a vortex or tornado-like phenomenon. Some people refer to these events as “firenado’s.”

Smoke, ash, fire, and water vapor are sucked upward into the atmosphere forming large fire-clouds that look and act like thunderclouds. The heat and particulates in these clouds inhibit precipitation, but like thunderstorms, the pyroCbs produce lightning strikes, triggering even more fires.

The other aspect of these fiery clouds, which perpetuates an ongoing disaster, is their ability to spread burning embers over large areas. The pyroCbs are hot and chaotic inside, with internal wind speeds reaching tornado strength. When a plume collapses, burning embers shoot out in all directions, literally raining fire on the surrounding countryside. This method of spreading embers wreaks havoc with any ongoing fire suppression efforts.

I didn’t see any news reported on pyroCbs in the Salem/Portland area, but they were on full display south of us in California. Fire tornados were reported spinning off several major fires. At one point, the Creek Fire sent a smoke plume 55,000 feet into the atmosphere, and pockets of flame reached up over 25,000 feet. The National Weather Service issued its first-ever “Firenado” warning as the Loyalton Fire peaked in Lassen County. Not only is the frequency of fires increasing on the West Coast, but the intensity of these fires is also ramping up.

No visibility, no water

I admire firefighters who take on the fury of mother nature at her worst. They study the fires and strategically plan where and when to fight for containment. They were hampered on some of the biggest Oregon fires by lack of visibility as thick smoke rose thousands of feet into the air. Visibility was too poor for water planes seeking delivery of their payloads to the areas most in need.

We followed the fire alert map religiously and watched as large swaths of land changed from green to yellow and then to red, signaling for residents to evacuate immediately. The fire alert scheme is cleverly simple — green, yellow, red or ready, set, go, where go means get the hell out of Dodge, now.

Fortunately, the fire’s advance was stemmed by Friday, and we currently hold steady at a level green alert. But fires are tricky, and we will keep our guard up until the ashes stop smoldering. These fires remind us we live on the margins of climate change, without the luxury of ignoring the science in favor of ideology. Reality is hitting home in many areas of the USA. Hurricane devastation on the Gulf Coast, fires on the Pacific Coast, Florida constantly flooding, farmers in the southwest don’t have enough water to grow crops, and melting permafrost in the Arctic is changing the tundra landscape.

When climate change goes local, it doesn’t seem like a hoax anymore. Your lens on reality sharpens when a changing climate results in hard personal decisions. Pragmatism takes precedence over politics when survival is at stake. Humans have a long history of procrastinating in the face of adversity until the fog lifts from their brains and critical thinking skills sputter back to life. Let’s hope this mental machinery will keep working as the privilege of voting comes our way this year.


Sources:

Climate Change Goes Local (By William House; Medium)

NASA’s Aqua Satellite Captures Devastating Wildfires in Oregon (Source: NASA)

With thick smoke, Portland’s air quality ranks worst in world (By Amanda Butt; KATU)

California’s wildfire smoke plumes are unlike anything previously seen (By Matthew Cappucci; Washington Post)

Feature Image: Wildfire (Modified by ArcheanWeb) — Original Credit: Photo by Marcus Kauffman on Unsplash

William House
William is an earth scientist and writer with an interest in providing the science "backstory" for breaking environmental, earth science, and climate change news.

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