Think Out Loud

Extreme heat and drought hit Oregon

By Kanani Cortez (OPB) and Elizabeth Castillo (OPB)
July 8, 2021 6:40 p.m.

Broadcast: Thursday, July 8

The recent record-breaking heat wave, a severe drought and the fear of looming wildfires have severely affected Oregon’s infrastructure, public health and agriculture. A recent study concluded that the deadly heat wave could not have occurred without human-caused climate change. We hear from Larry O’Neill, OSU professor and State Climatologist of Oregon, on what to expect for the remainder of the season and what mitigation measures are needed.


This transcript was created by a computer and edited by a volunteer.

Dave Miller: From the Gert Boyle studio at OPB, this is Think Out Loud. I’m Dave Miller. When the recent heatwave broiled the Northwest, meteorologists and climatologists ran out of superlatives and some started to question the validity of historical comparisons. After all, what good does it do to put an event in the context of history if that history is increasingly disconnected from our present, let alone our future. Meanwhile, yesterday a team of scientists tied the heatwave to human caused global warming. As one researcher put it, although it was a rare event, it would have been virtually impossible without climate change. For more on the heat wave, the ongoing drought and our changing climate, I’m joined by Larry O’Neill. He is an Associate Professor in OSU’s College of Earth, Ocean and Atmospheric Sciences and he is a State Climatologist of Oregon. Larry O’Neill, welcome to Think Out Loud.

Larry O’Neill: Thank you for having me.

Miller: Let’s start with the heat dome. When did you start seeing that something unprecedented was on the horizon?

O’Neill: Well, about 10 days before the event, the forecast models that we usually rely on to give us guidance on weather forecast began to show this very unusual, unusually strong weather pattern developing where we had this very strong high pressure system parking itself kind of over British Columbia in the North Pacific. The temperature forecasts in Washington and Oregon and British Columbia were absolutely insane, forecasting 110 or 120° high temperatures for places like Seattle and Portland and Salem, which is something that’s obviously way outside of our historical data records, the variability within it. So the conversation quickly turned to what is wrong with these models and why are they, why are they doing something that’s obviously not going to happen.

Miller: At that point, it was so far out of the realm of normal, that your assumption and the assumption of other experts was not that it was going to happen, but that there must have just been a wrong number built into the computer model.

O’Neill: Yeah or the processes of the physics that was, that the models used, there were errors in it or not necessary errors, but just they were picking up on something that wasn’t physically reasonable. The weather service hedged way lower than the temperatures ended up being. One of the things that happened is as the events became closer, so as we were kind of three days out, the models very consistently stuck to that story. It became clear that we were seeing something that was in fact going to be a historic heatwave.

Miller: With the passage of a little bit of time, now, can you help us understand what actually happened?

O’Neill: At least in terms of the meteorology, the high pressure system that the models forecasted actually verified. So it actually occurred and they, for the most part, the temperatures that the model said we’re going to happen did happen. A couple of really interesting things thinking about it is that the weather pattern at least was actually quite similar to other classic, heat waves that we’ve had the Pacific Northwest. We’ve had like a heat dome that kind of develops off of Vancouver Island and off the coast of British Columbia. That did transpire and that was consistent with previous heat waves. What was different about this one? So there’s a couple things that are different. One is that this system was just so much stronger than previous heat waves. In terms of the average temperature throughout the depth of the atmosphere, so the whole atmosphere was way warmer than normal. Second thing is that this heat wave was actually interacting with very severe to extreme drought conditions. And so, there’s some hypotheses that the fact that there wasn’t pretty much moisture in the soil at the time, that that might have helped limit the cooling ability of evaporation off the landscape. These factors were just completely, we’re still trying to work out exactly what the mechanism was for this extreme, for why this extreme event happened. But the other really interesting thing is that it’s still a bit mind boggling how much we broke all time temperature records. So in Portland, we broke the all time temperature record by nine degrees Fahrenheit. The nighttime minimum temperatures were also, it didn’t go below 70° for three days in Portland. So, Portland was really the epicenter of this heat wave.

Miller: And you’re saying the amount by which we broke the record is itself an important thing to focus on. It’s not just this at a new record, but it was the way in which the record was smashed. It’s something that is inescapable and important.

O’Neill: It is. I think it’s a very important component because this is, naturally we get heat waves throughout history, we get cycles of heat waves and cold waves and drought and not drought, but it’s the way in which, that just the magnitude that it broke, it was really surprising and it wasn’t just one day, what wasn’t just a one off day. It was three days of extremely warm weather, not just in Portland, but also obviously in British Columbia and Lytton that was over 120 degrees Fahrenheit. That close to the Arctic Circle, it’s really astounding and very, very worrying.

Miller: Yesterday, as I mentioned in my intro, a consortium of international scientists working for the group World Weather Attribution announced the results of a really fast analysis of this deadly heat wave. They found that it would have been virtually impossible without climate change. Can you help us understand what these scientists actually did, how they went about making this statement?

O’Neill: Yeah. So obviously we don’t have temperature records that go back thousands of years. We have to rely on our climate models to give us basically, our only way of trying to put this event in the content into historical context is by using these climate models. What they do in a very simple way is that they basically run a whole bunch of climate models over a very long period of time, back thousands of years and they do it in a couple different configurations. One is without any sort of greenhouse gas forcing anthropogenic emissions to the atmosphere, where you kind of get a baseline sense of what the climate variability would have been without our influence on it. And then they compare basically all the extreme events that happened within that data record to basically the climate that we are experiencing. They basically compare the extreme events that occur between the two and analyze statistically, kind of what the range of this extreme event was compared to a case where we didn’t influence the climate.


Miller: This has not been peer reviewed yet. And it was, as I mentioned, a very quick analysis, intentionally so too, so people in the news and people listening to the news, will pay attention to this and understand what scientists see as in ways that we didn’t talk about even 10 years ago, the connection between climate change and individual weather events. Do you think scrutiny like this will stand the test of time?

O’Neill: I think it will, and one of the reasons is is that there’s actually been quite a bit of analysis and study of both historical data record and then also other also these climate models and a lot more detail and these results that they come up with that they know their headline results they’ve done are actually consistent with a few other, several other analyses. So what it does is it contributes to a body of evidence that suggests that these heat waves are being made more intense by global warming. The actual numbers that they come up with, that maybe this was a one in a 150,000 year event, that numbers, you have to take it with a little bit of grain of salt. But the main conclusion that global warming had or climate change had a significant impact on this heatwave, I think is a fairly robust conclusion that agrees with other lines of evidence too.

Miller: Well, this gets to something that you tweeted out in the middle of the heat wave. You wrote: The problem with calling this a once in a 1000 year event is that the climate system is not in a balanced state. The past is no longer a reliable guide for the future. These events are becoming more frequent and intense, a trend projected to continue. How do you think we should be thinking about what this means for the future?

O’Neill: For the future, basically, when we start experiencing new things, at first it becomes a novelty or it becomes very hard for us to deal with it because it’s something we haven’t dealt with before. So, there is something about that we’ll start getting used to these type of events in the future, but it’s the first ones that we start experiencing that caused the most public health impacts, the most infrastructure impacts, the highest impact, because it’s the ones we haven’t experienced, the ones we haven’t planned for, and those are the ones, so for the next 10 years, when we start experiencing these things more often, it’s going to be harder for us to deal with until we start to adapt to basically having a different climate. It’s really important to note that this is just the start of a trend that we’re going to be experiencing and there’s really no way of getting around it. It’s not just a climate model predicting something, we’re actually seeing it directly in our data record and we’re seeing it directly ourselves. We also see the deadly impacts and also the other impacts on our ecosystems, our agriculture, and other things as well.

Miller: Well, let’s turn to that. Yesterday, the state of Oregon announced that 116 people have died because of the heat. And many experts have said that they expect that that is an undercount. What are some of the other effects that you’ve really been paying attention to over the last 10 days?

O’Neill: Yeah, so obviously, the most important are the public health impacts. These tend to occur more for vulnerable populations that don’t have access to adequate air conditioning or cooling systems or they can’t travel somewhere else and they’re just stuck dealing with it. And also people with underlying health conditions. Sometimes people move to the Pacific Northwest because of its cooler climate and they need that to maintain a proper health, things like that. So when something like this happens, it really catches people off guard. Some of the others, so there’s been a far range of impacts and I’ll just highlight a couple that we’ve seen. There’s obviously some infrastructure impacts. There were roads buckling, some kind of iconic images of that paralyzed infrastructure failed in many, in several places where, fortunately they were localized, but it just shows that this infrastructure was designed for, not for these sorts of temperatures. There were lots of reports of cooling system failures. Actually one impact that’s actually fairly significant that’s beginning to become more apparent is this extensive scorch of conifers in the coast mountain range, especially on the western side, and this affected both Douglas firs and cedars. There are reports and images I’ve seen from some of the forest managers, it looked like the hillsides, they were dusted in like this orange snow. So basically it got so hot that the needles on the trees basically kind of scorched. This is kind of an ongoing concern about what it means for the tree foliage loss and eventual mortality or stunted growth and whether this will contribute to enhanced fire danger as well.

Miller: What about agriculture? That’s something I know you’ve been focused on as a state climatologist.

O’Neill: Yeah, so the heat wave, this affected a lot of the agriculture in the Willamette Valley. Then also there are a lot of agricultural areas in eastern Oregon. Unfortunately, we’ve had a very early and severe drought. That’s basically, this is the second year of a multi year drought. So agriculture is already actually not doing well going into this due to very dry soils, not enough precipitation, shortages of irrigation water in many places and things like that, so that crop and pasture conditions were already suffering. This heat wave basically contributed to making the drought that much worse. So a lot of crops are being rated by the USDA as actually poor, very poor. A couple examples, winter wheat: over 70% of the crop in Oregon is considered poor, very poor and also barley and a few other types of grains and other things that rely mostly either on dry land, agricultural limit irrigation. So right now, things that are in irrigated fields that have access to irrigation water are doing okay. But it’s something that’s definitely a concern for the economy and for the well being of the producers in our region.

Miller: You mentioned fires, there are already fires burning right now in Oregon, including the Jack Fire near Roseburg, others in Klamath County. But we are still obviously in the early parts of a traditional fire season, an old normal fire season. What are your projections right now for the coming 2-3 to maybe even four months?

O’Neill: Yeah, so basically we had a historically dry spring. For the states of Oregon, Washington and Idaho, it was the second driest spring on record. That spans basically from March through the end of June and those records span back to 1895 and that has basically created conditions where there’s just not enough water in the landscape. We’re basically starting to see those effects. This heatwave basically moved up fire season a little bit more

by drying out fuels. The various metrics for flammability of fuels like what they call the 100 hour fuel moisture, 1000 hour fuel moisture, those have really increased, indicating very enhanced fire risk throughout. So basically, we can’t predict the future. We can’t predict any wildfire with any accuracy or whatever. But we can say that the risk of wildfire is very high from this point forward until we get those first wetting rains in the fall.

Miller: Before we say goodbye, now it’s being reported that there’s going to be another West Coast wide heat wave coming in pretty soon. More so for the American Southwest or places like Southeastern Oregon. But what are you expecting in the coming two weeks?

O’Neill: Yeah. At least for a lot of Oregon and Washington, this will be kind of more of our typical type of heat wave, possibly in parts of eastern or southern Oregon, it may get very hot, this coming heat wave may not be historic. But one thing is that some of the forecasts are actually projecting it to be kind of prolonged. Coming on the heels of the heat wave we just had, the impacts might be actually more severe, especially for public health and agriculture and for worsening our ongoing drought conditions.

Miller: Larry O’Neill, thanks very much for joining us.

O’Neill: Thank you.

Miller: That’s Larry O’Neill, Oregon’s state climatologist. He is an associate professor in Oregon State University’s College of Earth, Ocean and Atmospheric Sciences.

Contact “Think Out Loud®”

If you’d like to comment on any of the topics in this show, or suggest a topic of your own, please get in touch with us on Facebook or Twitter, send an email to, or you can leave a voicemail for us at 503-293-1983. The call-in phone number during the noon hour is 888-665-5865.