The $1.8 million view of BC’s floods and landslides
How an Abbotsford resident used his fancy camera to provide vital information for government officials and farmers during the Sumas flood.
Like plowing a field. Back and forth. Back and forth.
Far below Paul Gagnon, floodwaters were inundating one of Canada’s most fertile plots of land. Planting crops, at the moment, was far from the minds of most Abbotsford residents and officials. But above, in his plane, Gagnon found himself tracing lines familiar to anyone who has driven a tractor or mowed a large piece of land, and doing so to provide critical intelligence to those on the ground.
Gagnon started Peregrine Aerial Surveys a decade ago, with the aim of using aerial imaging to provide survey and mapping services. Gagnon’s company has since flown across North America taking pictures to help guide everything from development to disaster recovery.
In mid-November, though, Gagnon was on Sumas Mountain doing his best to just keep his own house dry. But as water filled the prairie below, he wasn’t surprised when the call came to take to the sky to gather images. Over the ensuing two weeks, Gagnon’s images would give government officials and farmers vital information on the eastward progress of the floodwaters, on the geography of the Barrowtown Pump Station, and on the status of highways into the Interior. Through his company’s Twitter feed, many of his images helped the public understand the seriousness of the flooding and landslides.
We spoke to Gagnon in late November, and then again last week, about what he has seen from the air, the images he provided, and the tools he used.
On the equipment:
Gagnon: We use Piper Navajo aircraft, their twin engine. Usually they seat about 10 people, but we take out the seats and cut about a 20-inch square hole through the fuselage and put our camera overtop of that so it points through the bottom. The camera fires based on GPS coordinates, so I have to get to a certain point in the sky, and then the camera fires automatically. So we set up these flight lines. And that’s why you’ll see in my images these square cutouts. So for that Sumas Prairie stuff, we were flying east-west flight lines, just like plowing a field back and forth. And it just automatically takes the pictures. Then we bring the hard drives into the office here and download the data. It goes through a multi-step process and takes a while; I think I was able to turn around the Sumas in about 24 hours from the time we were in the air taking photos to the time the client had them.
On flying in a straight line:
Gagnon: We use a GPS and an [Inertial Measurement Unit] for taking the pictures, and then we record that data for where it actually was taken. We’re within less than six centimeters in the air, usually around about three centimeters accuracy in the air for where that point was taken. So we already have the data for where to put that picture on the earth. And then we have a piece of software that takes those photos and lays them all out where the center of those photos should be. We take photos that overlap so you get a stereo view. You can actually see everything in 3-D if you have an appropriate monitor and software for that.
When we’re flying, we try to stay within 10 feet of this imaginary line in the sky—that’s when we’re having a good day and the winds are calm. Ten feet is pretty easy to do because of all our practice doing it… The six centimeter accuracy is for once the picture has fired. There’s a record taken of where that position is and the accuracy of that is within like three to six centimeters or so.
On his $1.8 million camera:
Gagnon: It’s pretty specialized for what it does. It’s the largest, single-sensor, large-mapping camera that there is—at least commercially available, I’m sure the military probably has their own thing. The one sensor in it that everybody looks at is the black and white that gets the sharpest [image] and that one is about 375 megapixels in that one sensor. And that’s black and white. I posted a picture of the bottom of the camera, and there’s a bunch of different lenses there. So there’s a black and white, a red, a green, a blue and a near-infrared sensor. So it fires all five of those cameras at the exact same time and then in the post-processing… the computer assembles those five pictures into one image.
On the view from the air:
Gagnon: From our altitude at about 1,000 to 10,000 feet, it’s hard to see the small landslides, but every highway that’s been washed out, you can see that pretty clearly. It’s almost terrifying to see the power that one landslide can do and just wipe out all the hard work and engineering that’s gone into making a highway. And then of course, the flooding itself is intense. It’s been something that we’ve never seen before, when I’ve been flying around. I’ve been doing this for about 10 years. And it’s just incredible. The amount of water that’s out there, it’s hard to just have them until you see it from the air.
On the power of aerial imagery:
Gagnon: Without seeing it from the air, it’s hard for us to imagine just how much water that actually is. And then when you see, oh, there’s a lake there now. And then you see these, just some of these houses sitting in the middle of a lake, that’s pretty sad to see that. But you can only see it from the air to get the big picture of things.
— Peregrine Aerial Surveys Inc. (@Peregrine_Air) November 25, 2021
On air traffic controllers during the height of the disaster:
Gagnon: It’s been very busy. I’ve had three pilots out there flying, me included. And it’s been the busiest that any of us have ever seen it, with all of the [aircraft], primarily all the helicopters, doing the deliveries back and forth and helping out. And then also, we ended up with the people that wanted to just go out and fly and see what it looks like. And adding everybody into the mix has just been really busy. So a shout out to the air traffic controllers for keeping us safe up there.
On being a part of a large effort and sharing images:
Gagnon: “The work that we do is one of these ones that I don’t think many people know about a lot. It’s not very much of their tax dollars, but they are paying for it. So I thought, it’s good to see what is actually being done to help you, you know. Seeing figures out there and all the heavy equipment doing the work. Those guys are working really hard. And we’re just here helping making the planning happen.”
— Peregrine Aerial Surveys Inc. (@Peregrine_Air) November 25, 2021
On the Chilliwack River:
Gagnon: One of the interesting things that I saw was the changes in Chilliwack River from a non-human tragedy perspective. It was interesting seeing how the rivers changed—and it will remain changed, with the new pathways in some areas, even once the water goes down. It’ll be interesting to see what that looks like.
— Peregrine Aerial Surveys Inc. (@Peregrine_Air) December 10, 2021
On the changes from the first flight (Nov. 17) to the last (Dec. 3):
Gagnon: It was pretty disturbing seeing all that. We don’t usually do a lot of disaster things. But this was right in our backyard and obviously we wanted to go up and do it. And the last flight here on the third where we can see the water is receding really nicely, it’s nice to see. I’ve had some specific requests from certain properties, where… they were like, “Hey, can we see just how bad our farm was?” So that was kind of nice to be able to provide. Some of them were pretty inundated with water. One of them still is, unfortunately.
[The flight path over the prairie] is how we get in and out of the airport every time we go flying, so it was quite a drastic change. So our hearts go out to everybody that lives out there. One [property owner] had asked me for a picture and their property is just covered in debris, like it’s absolutely covered. And just looking at it, it would take me weeks to just pick up every little piece of wood that’s sitting in there. Garbage floated into their property and now that the water is receding, the debris isn’t leaving, it’s just now in their yard. So they’ve got to deal with the flooding in their house and this massive cleanup outside the house as well.