Portland State University researchers define extreme 'heat domes' 12%
By Hannarose McGuinness27%
8/4/2026, 4:02:26 AM
BS Summary: This article contains 21 faulty reasoning types, including Appeal to Authority, Negativity Bias, and Post Hoc (False Cause), with Availability Heuristic as the most egregious example at 8.2% saturation with 62 hits. Analysis detected 641 faulty-reasoning hits from 756 analyzed words, generating a BS Score of 22.3% and a BS Rank of 12% (24,835 of 27,984 articles). This article is better (less manipulative) than 88.70% of the article peer group.
Summers can bring scorching temperatures to the Pacific Northwest and scientists at Portland State University (PSU) are working to define a term for one of the most extreme heat events plastered across media outlets.
In 2021, Oregon and the PNW greater region experienced a scorching heat wave that broke records, the effects of which killed at least 120 people and impacted infrastructure, agriculture and forests.
The event was so significant that it became known as a “heat dome.”
The American Meteorological Society defines a heat dome broadly as an exceptionally warm high-pressure system that can have a “doming” effect impacting large regions.
But the group using the term most often is media, not meteorologists.
So PSU researchers set out to define a heat dome with measurable values.
Associate Professor of Geology Paul Loikith and PhD Candidate Siiri Bigalke were part of the team of researchers spearheading this work.
They wanted to provide the scientific community with a definition that included more specificity, numbers and thresholds to objectively differentiate between heat waves and heat domes.
Defining a heat dome
Loikith said their recent paper defines a heat dome as an area of high pressure in the upper atmosphere that brings extreme surface temperatures.
The definition describes both a circulation feature of high pressure in the atmosphere and a connection to surface temperatures in the top 1% of extreme heat temperatures.
The heat domes also had to affect an area of at least 150,000 square kilometers, or an area slightly larger than the state of New York.
“That area of high pressure is really what we can picture as being the ‘dome’ of the heat dome,” Loikith said.
“So it's almost like an expansive bubble of hot air over the surface.”
Bigalke said she has heard the phrase “heat dome” used a lot since the 2021 heat wave, but said it was never a formal meteorological feature discussed in her coursework.
She said there was a disconnect between what the scientific climate and weather communities know and how weather events are communicated to the public.
She saw a need for the public to understand atmospheric features while also having a scientifically robust definition for the term.
Are 'heat domes' new?
Loikith said events that fall into the category of “heat domes” have been happening for more than 80 years.
So while the term ”heat dome” gained media popularity in the 2010s, the phenomenon has been happening much longer.
He said as we experience more heat waves, the likelihood of them being qualified as heat domes increases.
“We use data going back to 1940 and heat domes occurred in almost every year going back to 1940, so they aren't new,” Loikith said.
“...
Everything is being measured relative to the historic climate, which was cooler.
So just by the very fact of everything warming, you get more candidates of extreme heat that could be a heat wave.”
Bigalke said 70% of the heat waves in North America are connected to a heat dome event at one point in a heat wave’s life cycle.
The report found the American Southwest has the greatest proportion of heat waves caused by heat domes.
PNW's 2021 heat wave still being studied
She said the 2021 heat wave was “astounding” in how anomalous it was and how often it is still studied.
She said it was a heat dome that probably hasn’t been seen in modern history.
“Something I'm always continuously amazed by is the fact that the Pacific Northwest 2021 Heat Dome just is continuously studied in our community.
There are papers coming out about it all the time, still even five years later,” Bigalke said.
“That event in particular was extraordinary.”
Loikith said, “Our heat wave really changed the world,” and the study of heat events.
He said he had a lot of anxiety going into the 2021 heat event because he felt like people were not taking it seriously enough without a comparable reference point.
“We have other weather features that we have names for, like a hurricane and an atmospheric river.
Ultimately, what matters is whether people get lots of rain or lots of wind,” Loikith said.
“But having these names to these features does bring some attention to them that I think has proven to be beneficial to public warnings and mobilizing emergency management.”
Research continues to develop more scientific specificity on what drives heat waves.
Hannarose McGuinness is The Register-Guard’s growth and development reporter.
You can reach her at hmcguinness@registerguard.com.
Speakers
2speakers63%attributed speech276writer words
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100%flagged-word coverageSiiri Bigalke
182 attributed words38% of attributed speech51% writer coverage
Attribution is sentence-level. Pattern percentages are calculated only from words assigned to that voice.
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