More than 2 million Oregonians live in drought-stricken areas. Dry summers in the Pacific Northwest affect various industries, including agriculture, water supply, fisheries and hydropower. But could science change that?
Cloud seeding is an 80-year-old technology in which tiny particles, often of silver iodide, are added to clouds via aircraft to help trigger rain or snow.
Rainmaker, based in California, has been testing this technology using drones in areas across the country, including in Pendleton.
Parker Cardwell is the chief operating officer for the company. He joins us to share more on what cloud seeding is and what the company has learned in Oregon.
Note: The following transcript was transcribed using AI and validated for accuracy, readability and formatting by an OPB volunteer.
Dave Miller: This is Think Out Loud on OPB. I’m Dave Miller, coming to you today and all this week from Hermiston in Umatilla County. This county, along with a lot of the rest of Oregon, is under a drought declaration. It’s a result of one of the warmest winters in state history and historically low snowpack. My next guest says that a new twist on a relatively old technology could provide some relief going forward. Parker Cardwell is the chief operating officer of the California-based company Rainmaker. It’s been using drone-based cloud seeding to trigger snow and rain. Parker, welcome to Think Out Loud.
Parker Cardwell: Dave, thank you so much for having me on today.
Miller: Your company was featured in a recent article in Harper’s Magazine. I wanna read folks a short excerpt from it cause I feel like it helps us set up the history of this a little bit. This is what the writer wrote: “Weather modification is among the oldest and least successful human projects for thousands of years. We have sacrificed children, sung songs and danced, brewed alchemical concoctions, chanted prayers, fired cannons, and made many other futile efforts in the attempt to somehow change the weather a little more to our liking. Stubbornly, the weather persisted, seemingly undisturbed by human action until the 20th century.” OK. So, Parker, in the 20th century, about 80 years ago, people came up with the idea of cloud seeding. What are the basics of how it works?
Cardwell: Like you said, cloud seeding was actually invented here in the United States, in upstate New York, by a couple of General Electric engineers. And like you said, drought, historically, has not just been scarce, but also sacred. We’ve been trying to find ways to enhance precipitation for water supply for centuries now. What cloud seeding is, is essentially just mimicking the natural precipitation or rain and snow process.
What happens is, you get these clouds that come across the Pacific Ocean that are full of what’s called supercooled liquid water, basically liquid water content that exists at subfreezing temperatures but hasn’t yet frozen yet to form ice crystals and then fall as snow. So what happens naturally is you get dust, sand, or pollen that comes off the ground from the wind into the clouds and then acts as this centerpiece for a snowflake, that once they aggregate more water onto them, become heavy enough to fall as snow or precipitation.
What cloud seeding does is essentially introduce a dust particle that has the same shape of that ice to basically either kickstart that snow process or, if it is snowing a little bit, squeeze a little bit extra precipitation out. So, historically what we’ve seen is about a 10-20% increase in precipitation across a given event. That’s the basics of cloud seeding, but happy to dive down deeper if it’s helpful.
Miller: Well, the first place I want to dig into is what you’re doing that’s different from what those folks would have done in upstate New York 80 years ago. What have you introduced in the 2020s that they wouldn’t recognize?
Cardwell: Certainly. There’s two primary points that made really the key of Rainmakers’s innovation. The first being the physical validation that we’re using to quantify our operations. Historically, for the last 80 years, and even a lot of the old antiquated operators of today, are using statistical analysis. This is just basically looking at what happens in one cloud compared to another, or one basin compared to another, which, there’s no two clouds that are similar, there’s no two basins that are similar.
What Rainmaker uses is radar and satellite-based physical validation, which is essentially seeing what is happening in the cloud that we’re operating in so you can see what’s called reflectivity increases on the radar. In a cloud that is not precipitating, it has a very low signal, so you’re getting this low reflectivity. But when you start to see the cloud activate and start to precipitate, that reflectivity is going to increase. So what we can basically see is, one, it’s working in real time, and then, we run a similar method that the National Weather Service uses to quantify precipitation over our operations as well. So we use the same thing that we use to measure our rain and snow today to basically just see the area where cloud seeding is working, and then following those radar tracks down to the ground to measure in acre-feet how much snow we actually produced.
Then the second point is using drones for cloud seeding, rather than traditional aircraft or ground-based methods. What drones unlock is far more precision and efficiency in our operations. So what Rainmaker brings is a real sophistication to a cloud-seeding operation, not just scientifically but operationally, being able to target specifically which clouds have this supercool liquid water. And then our drones can navigate up to 18,000 feet in those clouds, survive the severe icing conditions that would ground most aircraft, and allow us to be far more precise in where we’re actually operating, which is going to yield the most water supply for our partners.
Miller: That article that I mentioned in Harper’s, the reporter went to the Pendleton testing area, not far from where I am right now, and watched some of your drone operators as they, over a long night, tried this out, in various instances. What are they waiting for? To decide, yes, we’re gonna send the drones up and we’re actually gonna do the seeding. What are the right parameters for any particular cloud?
Cardwell: Yeah, certainly. It’s very important to note that we can’t create weather or we can’t create clouds, so largely, like we say, we have a very close partnership with Mother Nature. We’re waiting on these clouds to come across Pendleton, which has been an enormous partner for us as well up at the drone range, right there by the airport. What we’re waiting for are these clouds that have a high concentration of liquid water, and to make sure that that liquid water is cold enough to actually kickstart the process.
So what we’ve seen through our research, and then the historical research that’s actually fairly accurate, is that cloud seeding starts to work when that liquid water is about -6°C or 21°F or lower. So we’re really waiting. We’re sending up weather balloons, we’re launching our drone that has onboard pressure and temperature and humidity sensors, to validate the right conditions for the right moment so that we can actually start to do the process.
Miller: What are you actually seeding the snowflakes with? If Mother Nature relies on bits of pollen or dust or whatever, what are you using?
Cardwell: We’re using a material called silver iodide. It’s been shown through a number of university and third-party researchers to be incredibly safe, both on the soil and the water and for plants and whatnot, but it’s actually the historical material that has been used. And because of its efficiency and safety profile, it’s actually a similar one we use today. We just use it far more directly, and more efficiently.
Miller: How much stuff are you putting into those clouds to get them to form snowflakes or raindrops?
Cardwell: A given operation will be about 20 to 40 grams of silver iodide. So we’re talking about a bag of Skittles worth, essentially, a very, very small amount. Essentially what Rainmaker is doing is really just working and nudging Mother Nature in the right direction. So once we can kick start that process, what happens essentially is ice crystals then begin to grow and the natural precipitation process starts to occur. Once we initiate, the natural process really takes place, so we don’t really need to intervene too much.
Miller: In other words, once you put some of these particles in the air, more rain or snowflakes are likely to form, even if they’re not surrounding the particles of the silver iodide. You sort of jumpstart it and create a kind of chain reaction?
Cardwell: Yeah, exactly. What happens naturally and with our operations is these ice crystals start to form in the air in one part of the cloud, and then they break apart and then create new centerpieces for new snowflakes to occur. And so what we’ve seen through a lot of our operations these last couple of seasons has been that that reaction or that process will occur for around an hour to maybe two hours in the biggest event, and then start to dwindle off, like a natural rain or snowstorm would. That’s how we’ve seen it in the live operations.
Miller: What happens to the silver iodide once it falls to Earth?
Cardwell: It essentially just falls down with the snowflakes, and once it’s on the ground, it’s fairly indistinguishable. You’re using such a small amount, so over a large basin, it just kind of sits there afterwards.
Miller: How did you choose Pendleton as a U.S. testing area?
Cardwell: Maybe as an Oregonian, it was my bias to just wanting to be home, but really what it was is that Rainmaker has developed the most capable anti-icing drone in the world, really, and early on – obviously it’s a pretty audacious claim to make – but early on in the process, the FAA, which regulates aircraft and drone flights in the U.S., wanted to see that we had the right safety protocols and the right technical capabilities on that aircraft to give us a waiver or a permit to fly in airspace. So Pendleton has the UAS Range attached to their airport, which is essentially an airspace sanctuary. It’s where you see a number of drone operators like Amazon Wing that do the drone deliveries. It’s basically a range where companies can go and test next generation frontier aircraft.
Miller: Let’s actually get into this. The company is called Rainmaker. From what I’ve read, primarily what you’ve been doing is creating snow. How big a difference is there between making snow fall out of a reluctant cloud and making rain fall?
Cardwell: What we’ve seen, I guess it’s really a draw back to Oregon this year and the, what, 91% of the state that’s in drought conditions – I think 21 out of 36 counties declared by the governor to be in drought conditions – that this last winter was actually a snow drought for Oregon. So, the difference between rain as precipitation and snow is that rain, although good for crops and good for some surface water and aquifer recharge, it doesn’t sustain.
With snow, largely snow is the greatest reservoir in the west for water resource management. Essentially what happens is you get the snow in the mountain ranges, and then in the spring and summer
months as the snowpack starts to melt, it starts to feed our water resources. So by increasing snowpack, you create a more sustainable long-term feeding of our water system. That’s why Rainmaker, we primarily focus on snowpack for our operations because of its consequence for spring and summer agriculture, hydroelectric production, as well as just water availability across the west, primarily.
Miller: Is it easier to make snow than rain?
Cardwell: It actually is. In the winter time, although, when you get the high winds and it’s far more cold, I think the challenge of the clouds is hard from an icing perspective. But rain clouds have a lot more of what we call convection, or just very violent winds, so it’s harder to operate in those systems. But most importantly, we do snowpack enhancement because we’re able to differentiate in a physical way our actual effects.
We’re able to quantify using physical validation how much water we produced in the wintertime. In the summer, it’s harder to find that signal of how much actually you’re increasing and how much you’re creating. So for us and our partners, one thing that we know very deeply here at Rainmaker is that snow or water, broadly, is only as valuable as you can meter it. So if you can’t show how much water you produce, then it’s really hard to account for that in the system.
Miller: It’s only as valuable as you can meter it if this is a business. It’s valuable for anybody who gets it, right? I mean, I take your point, but let’s turn, then, to the business side of this. What is your company’s business model?
Cardwell: To your point too, for a lot of the water managers, whether it be the state department of water resources or a local irrigation district, to be able to know how much water you’re able to deliver to your senior or junior water rights holders for their water management, being able to meter is everything. So for us right now, our primary mode is essentially just in operational services. We work between November and April to produce as much snowpack as we can, and then for our partners we’re delivering that number of acre-feet that we’re producing for them. So this goes into allowing them to at least account for how much more water they can expect in the spring and summer and then know how to allocate accordingly.
Miller: Who are your potential customers, or your actual customers?
Cardwell: Right now we operate the largest cloud seeding program in American history in Utah, actually between the state of Utah and the state of Idaho in the Bear River Basin. We largely partnered with the Department of Natural Resources and Water Resources across both states, and then we have another partner companion on the programs with the local water and irrigation districts as well. So we work with these government entities to develop a strategy that’s bespoke for each basin and each watershed, so we know that where we’re producing the snow and where we’re putting that is the most valuable for their water resource management.
Miller: Could somebody credibly accuse you of stealing the snow that would have fallen further east because you cloud seeded it before it got to them?
Cardwell: Yeah, we certainly understand how… This is a natural first question for a lot of people to ask, and what we’ve seen through historical research as well as our own internal research, is that actually, cloud seeding creates a much more efficient system. You see either similar or net positive results downwind. Essentially what we call this is, it’s like a hydrological resaturation, and once you’re putting more water on the ground, that humidity and evaporation from that water will then resaturate the clouds.
So what we’ve seen is clouds behave very normally as they would downwind of our operations, and largely this is because actually topography or mountain ranges are one of the biggest causes for precipitation or snow. So we seed in one area, it’ll stop snowing, and then if it runs into the mountain ranges, whether it’s the Cascades or the Blues, you’ll see it start to naturally precipitate as it would have originally.
Miller: Did you see that in Utah’s Bear River Basin over the last year? Because my understanding is that a couple of months ago, your company announced very proudly that you increased snowpack in the area where you were working. Was there also an increase in the area downwind?
Cardwell: Well, what we saw was, we were primarily looking within the Basin, but what we saw is that the basins adjacent to our areas were on par with what the surrounding areas would have looked like anyways with drought conditions. We were really excited to be the first private company in history to repeatedly and unambiguously show that we can produce water. So that was a big step. It was the first operation ever to do that in the United States, so to be able to show that to Utah was a great step forward. The results in the Basin were incredible, and it was a good launch pad for next seasons, but around that, we were kind of in an area where anything downwind of it was blocked by the mountain, so it’s no different than what we were anticipating.
Miller: But I guess I’m still trying to figure out the downwind effects, because it does seem like a little bit of a magic trick. If you’re saying that you could increase snowpack in the area where you are operating without impacting the areas further east, where is that moisture gonna come from in the arid West?
Cardwell: Yeah, I’ll note this is that clouds are actually fairly inefficient at producing snow or rain, and so what we see is that only a very small amount, 7-9% of the water from the atmosphere of these clouds ever precipitate out to touch the ground. And so when we are seeding, we’re only encouraging an extra 1%, maybe 2% of that water to fall. So the ample amount of moisture that’s already ambient in the atmosphere in those clouds is going to basically supply more than enough downwind.
Actually, what we’re seeing is that there’s far more water that stays in the clouds and stays in the atmosphere as it progresses east and then evaporates and falls back into the ocean. So essentially what we’re taking is just a slight chunk out of it to benefit the areas that we can produce it, and then downwind you’re going to see that natural effect, because, again, we’re taking such a small amount out. It’s consequential for the communities and the partners that we’re working with but it’s very inconsequential in terms of the total water quantity in the atmosphere.
Miller: We’ve been focusing on the U.S. and really the U.S. West, but what are other countries doing right now in terms of their own efforts at cloud seeding?
Cardwell: There are about 40 countries throughout the world that are actually employing cloud seeding right now. For them, a variety ranges from rain enhancement for reservoir refilling, snowpack enhancement for glacial restoration, but all of it really does revolve around water supply as the primary mode. As we see the West and the United States be far more exposed to drought conditions, we’re not the only ones throughout the world that experience this.There’s obviously far more drought-ridden countries throughout the world.
So any cloud seeding is not a silver bullet. It’s not going to end drought overnight. It takes a myriad of technologies, whether it’s evaporative loss prevention or better piping to remove water loss into the ground. There’s a lot of water technology that needs to be employed to manage drought, and these countries around the world see cloud seeding as a tool to just supply additional water.
Miller: Parker, thanks very much.
Cardwell: Yeah, thank you, Dave, really appreciate it.
Miller: Parker Cardwell is the chief operating officer at Rainmaker.
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