April 3, 2021: Satellite Saturday

I haven’t received many aerial photographs lately, so Ice Patrol has been a bit quiet. Also, we had a couple of days of cold temperatures, so there wasn’t much to report.

Satellite imagery from the last week was a bit baffling. Changes to the ice made it appear as if the lake was refreezing, and then some fresh snow made things look streaky and weird. But today was sunny and warm, and the NASA satellites got a good look at us.

Let’s start with today. Here’s Terra’s MODIS image from this morning.

If you click on this first image, you’ll see a version with some landmarks tagged.

Terra satellite’s MODIS image from April 3, 2021, in natural colour.

And the false colour version, which incorporates some infrared and gives a better idea of the quality of the ice.

These images are just 640×640 pixels, so you cannot zoom in on them.

Terra satellite’s MODIS image from April 3, 2021, in false colour.

For the last ten days or so, the satellite images have been a bit hard to interpret, so let’s go back almost two weeks to see how things looked on March 22.

Aqua satellite’s MODIS image from March 22, 2021, in false colour.

I have to say, the differences are subtle, and not clearly in this week’s favour.

But if you’ve been following the comments, you might have noticed Eroc’s post that the webcam at Red Wing Lodge, near Morson, Ontario, is showing a lot of candled ice and open water. If you’d like to take a look for yourself, I’ll add a link to the lodge’s homepage on the Lake of the Woods Links sidebar. There’s a link to the Flag Island Webcam, too. I just checked, and the ice looks really rotten there.

So I think most of the paler blue in the latest picture, which normally represents thicker ice, is actually candled or air-filled ice.

The other thing I’ve been wondering is: how does this year—with such an early start to the thaw—compare to other years?

The two years I’d be most interested in checking are 2010 and 2012, because they both had early melts and were ice-free by the middle of April.

2010 was cloudy for the whole first week of April, so there are no satellite pictures suitable for a direct comparison.

But in 2012, Terra got this lovely image on this exact date.

Terra satellite’s MODIS image from April 3, 2012, in false colour.

Okay, there’s no getting around it. 2012’s thaw was way more advanced on April third than we are this year. But don’t feel bad. 2012 was a very early thaw: the lake was clear by April 16.

What does a more typical year look like? Well, the first five days of May is a very common ice-out range, so the best years to check would be 2015 or 2016. Presto! Terra got a good shot on this date in 2015.

Terra satellite’s MODIS image from April 3, 2015, in false colour.

So in a typical year, early April has the lake pretty much frozen solid except for some of the narrows.

We’re doing well, and the forecast is for above normal temperatures for the next two weeks. A normal high this time of year is 6°C, and overnight lows would average out to -4°C.  We’re forecast to be above freezing almost all the time, and we’ll have some lovely warm days in the next little while.

My conclusion: we’re still on track for an ice-free lake in late April.

Signs of Spring: Motorcycles. I’ve seen several, and have made a note to be more alert for them. Please try to do the same.

Also bugs. This is one of the powerline clearways on Tunnel Island. You could click on this picture to see it full screen, but trust me, it doesn’t get any prettier.

Swarm of flying insects.

Blackflies? Sandflies? Gnats? I didn’t stick around to find out. I snapped a quick picture and left. Note to self: either take my Covid mask on hikes, or grow a moustache long enough to breathe through.

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