Just in case you were wondering when the last ice in Ontario melts, here’s a picture of it.
Big Trout Lake is over 500 kilometres north of Kenora, and as you might guess from the name, it is both large and deep. There are lakes further north, but because they’re smaller and have more current, they thaw earlier.
I believe Lake of the Woods is 100% ice-free today. So here’s a look at how the spring went, in graphs. You can click on the graphs to see a full-screen, zoomable version.
First, the Brick Graph. Each year gets a brick, and I stack them according to when the ice went out. For simplicity, I divide April and May into five-day periods.
2019 was not an early thaw. Of the last sixteen years, only 2014 was significantly worse, and that was a dismal spring after a brutal winter.
Here’s a slightly more complex graph, that shows not just the date the lake was clear of ice, but the length of time from when it started melting to when it finished. More specifically, each horizontal bar spans the calendar from the Inflection Date, when the mean daily temperature rose above freezing on a lasting basis, to the Thaw Date, when the lake was entirely free of ice.
2019 is at the top, 2018 just below, and so on, down to 2008, the earliest year Sean worked out an inflection date for.
Some fun trivia from this graph: Our inflection date was April 13th this year. 2016 shared the same inflection date, but the lake cleared by May 4th, a full ten days earlier. The ice was probably a lot thinner that spring, because the winter had been mild. 2010 was an extraordinary year: the lake was completely clear by mid-April!
Here’s a graph from Sean that shows how our spring temperature profile compares to other years.
On this graph, all the springs are lined up with Inflection as Day Zero at the left regardless of the calendar date. Each year gets dots in a different colour, and day by day, the mean temperature is added to the rising total. A spring with a string of hot days will produce a steep rise, a cooler spring will show a flatter line. The solid red line is the average for all the years since 2003. 2019 is the thin blue line, and Sean points out that although we did better than average at first, we fell behind about halfway along and never quite caught up.
Anyway, that’s the kind of spring it was, but the lake’s open now. I won’t be doing regular updates any more until next year. I expect I’ll fire up the Ice Patrol again on the first day of spring, or the inflection date, whichever comes first.
Thanks to everyone who came by to visit the website and shared word of it with friends, and a special thanks to my guest photographers and my co-workers at MAG Canada who made it possible for me to offer updates on days when I didn’t fly.
Talk to you next year,
Tim
Today I went looking to see if any ice remains on Lake of the Woods. I did find some, south of the Barrier Islands, but it’s just little patches of loose, candled ice.
The photo above is from around 10:00 this morning, and looks south over Allie Island towards the Alneau Peninsula. I’ve circled the area of interest so you’ll know where to zoom in for a better look. At full resolution, that’s clearly ice.
I thought a little patch of weak ice like that wouldn’t last long, so I was looking forward to checking on it on my return in the afternoon.
We came back at about 5:00 and after checking to see that Big Sand Lake, north of Minaki was open, (too far away to photograph, but it is open) I started with a picture of Shoal Lake.
As far as I can tell, Shoal Lake is wide open. Because it’s deep, It often clears about three days later than Lake of the Woods, but this year it cleared earlier.
Next shot, Big Narrows.
Looking south. Left of centre is Wiley Point, with Big Narrows above the middle of the picture. In the distance, is that ice on Little Traverse? It was so hazy I wasn’t sure, but there was ice there the other day.
Next, I checked on that ice south of Allie Island.
In the centre of the picture, you can see it’s falling apart, but it’s not gone.
There was a lot of discussion about Bigstone Bay over the weekend, so I wanted to get a bird’s eye view.
This picture is centred on Scotty Island, with Middle Island and Hay Island stretching away to the right. Bigstone Bay appears to be entirely clear.
Next, a closer look at Bare Point and Pine Portage Bay.
Bare Point Marina and Northern Harbour, on Pine Portage Bay, are key access points for Bigstone Bay and Hay Island. Both are wide open now. I counted about twenty boats in the water at Northern Harbour this afternoon. There might be more, but the bigger boats are easier to see.
So although a small amount of ice persists, the lake is essentially open for boating.
Let’s go to the satellite imagery, Bob.
Aqua‘s image was spoiled by cloud today, but Terra got a pretty good shot. The white circle encompasses Rabbit Lake, Round Lake and Laurenson’s Lake, which are good markers for picking out Kenora. The small red circle is the surviving ice south of Allie Island. The large red circle indicates the area of possible ice on Little Traverse, but the satellite image shows nothing except a streak of cloud.
Fun with Clouds, Part Two: at the top left, our friends the fair-weather cumulus. At the right, in blue, high altitude clouds made of ice crystals. In the lower part of the picture, clouds of vertical development: towering cumulus or nascent thunderclouds, with watery bases and icy tops. When clouds like this become full-grown thunderheads, the vertical movement of water droplets up and down through the freezing level forms hailstones.
Summary: only one tiny patch of weak ice remains on Lake of the Woods today, and it will be gone tomorrow.
That means we’ll be ice free on exactly the same date as last year, which kind of makes sense given how the winters were similar in both duration and coldness.
I say kind of, because although the winters had a lot in common, the springs were quite different. 2018 was a late, cold spring that turned really warm at the end of April. 2019 was a slow, cool spring with few warm days.
Here’s Sean’s updated graph of our temperature progress this spring.
Overall, you can see we had moderate thawing this year, with the blue dots showing that mean daily temperatures added up slowly, especially in late April. When Sean and I first modelled this year’s forecast, we chose a thaw index of 240, because that’s how much heat it took to melt last year’s ice, and the two winters were similar. In the end, although the predicted date for ice-out came close, the actual amount of heat it took to do it was less than we thought, and this graph shows a revised forecast with the expected thaw index reduced to 190.
Basically, we assume that a long cold winter makes lots of ice, and it will take lots of warm days to melt it all. That’s simplifying, and we know it. The brutal winter of 2014 thawed with an index of 194, so 190 is not unreasonable. Perhaps last year’s 240 points was an oddity.
In any event, we didn’t need as many thaw days as we first thought. Sean offers these technical insights:
Sources of error are plenty in this high level statistical analysis. Wind, direct sunlight, rain, ice thickness, snow thickness etc are all variables that the analysis does not take into account.
Our ratio of freezing index to thawing index was right around 10 this year, which is the average for the last 15 years or so. Our initial prediction this year was conservative based off of last years data and went with 7.5 freezing index to thawing index ratio.
If we had ignored last year’s unusual thaw, we would have used a ratio of 10 and gone with an index of 200. That would have been close.
That’s basically it for this year. I’ll do a wrap up post when I can confirm that last patch of ice is gone, and I’ll update the different graphs that show how this spring compares to recent years.
Now that boats are hitting the water, it’s time for my annual reminder that the stretch of Safety Bay from Bush Island west to Norman is a licensed Water Aerodrome: an airport for float planes. Please watch out for them when boating in this area. Think of it as a runway. For safety reasons, float planes have the right of way when taking off or landing. When taxiing, they are supposed to be like any other watercraft, but from experience, I can tell you that they cannot decelerate quickly or turn sharply. Do be careful around them.
Jason Sugimoto sent me these pictures from the Sioux Narrows area today, and a screen capture of a map to show where they were taken.
Jason says: Was just out in Sioux Narrows and still some rotten ice in Whitefish Bay. Regina Bay looked ice free but didn’t venture too far into it.
Since this one shows the power line, it might be from the more northerly location.
Bear in mind that the aerial or satellite images you see at Google Maps are not current; they’re file images. The forest is not that green yet.
I think this picture’s from the more southerly area.
Jason says: The ice was quite rotten and was able to push through it slowly with the boat.
Thanks, Jason!
In other news, if you haven’t been reading the comments*, you may not have seen David Foerster’s report that Clearwater and Ptarmigan Bays are clear now.
*If you follow Lake of the Woods Ice Patrol primarily by email, you may miss some of the website’s extra features: comments, links, an archive of previous years, and the ability to scroll quickly to recent posts, or select them from a list. For all Ice Patrol has to offer, drop in on icepatrol.ca once in a while.
Signs of Spring: the snow is almost gone from the Seven Generations parking lot on Veteran’s Drive, the trees are finally starting to leaf out, and Safeway has put the ‘take a number’ dispenser back up at the deli. Seriously. They only use it in the summer.
Aqua didn’t get a perfect look at Lake of the Woods today, due to some high thin cloud, but Terra had an unobstructed view, and got a beautiful sharp image.
Here’s the false-colour version first:
The three large ice sheets seen yesterday—on Shoal Lake, in Little Traverse, and south of the Barrier Islands—have all shrunk dramatically. The smaller patch on Bigstone Bay seems to have gone completely.
Fun with clouds: the fair-weather cumulus clouds at the left edge of the frame are low: you can tell because their shadows are sharp and tight.* The big patch of cloud in the upper right corner is higher, and the shadow is softer and wider. The cotton-candy clouds at the lower right are higher altitude, so their shadows are fuzzy and widely separated. It’s cold up there; these clouds are blue because they are composed of ice.
*When I see drifting herds of clouds like these over the prairies, I call them buffalo ghosts.
Here’s the natural colour version of the same image:
The details of the lake don’t stand out as well, but the ice is very plain to see. Interestingly, the city of Kenora is easy to spot: look directly above the most northerly ice sheet, and you’ll see a sprawling beige area. That’s Kenora. Now that you know where to look, squint at the false-colour image, and you can make out our three suburban lakes: Rabbit, Round and Laurenson’s.
There’s a bit more to say about Bigstone Bay. Keep in mind that a sheet of ice a kilometre square would only be a tiny speck of four pixels on one of these satellite images, so absence of evidence is not evidence of absence.
I got this comment from Jeff, who finally reached Hay Island this afternoon.
I made it to Hay, all of Bigstone ice free, except for some in front of Smith Camps, which that is likely gone by now or close to.
Smith Camps is located on Thunder Bay, just east of Pine Portage Bay and Heenan point.
I received this picture from Ted Main at about 3:00 this afternoon.
Ted says: Here is a picture from Thunder Ridge Road (Heenan point) facing north to Northern Harbour.
There are patches of candled ice in the foreground, and perhaps a more extensive sheet towards Pine Portage Bay in the distance.
A note on the weather: a week or so ago, the outlook was dismal, with temperatures expected to run consistently a little below normal until the second half of May. We did better than that today: we spent several hours at 19ºC this afternoon, which is actually slightly above normal for mid-May. It was lovely. I got the patio furniture out, and we had drinks on the deck. The Weather Network’s 14-day forecast now says that although daytime highs will run a little shy of normal, overnight lows will be on the mild side.
Here’s today’s satellite image from Terra.
This picture’s a little blurry, but it’s clear enough to tell the tale. Shoal Lake is trying to hide under a cloud but there’s still ice in the main part of Shoal. On Lake of the Woods, a large sheet of ice survives on Little Traverse, and there’s a smaller sheet south of the Barrier Islands at the centre of the picture. Just above that is Hay Island’s distinctive “battleaxe” shape and although I thought Bigstone Bay might be fully open, there’s still a fuzzy blue patch there, representing weak ice.
There’s no longer any ice visible in the Clearwater Bay or Ptarmigan Bay areas, but anything less than a kilometre square (four pixels) would be invisible at this resolution.
Just got these aerial photos from Andrew Kozlowski. He took them around 7:00 this evening.
Scotty Island, looking south west at the Barrier Islands. Those long, straight bits of ice on Scotty’s shore are remnants of an ice road. Looks like there’s still some significant ice south of the Barrier Islands.
This is Whisky Island, also looking roughly south west. The Manitou is clearing out.
It won’t be long now.
Thanks Andrew!
