May 3, 2020: Tipping Point

Yes it snowed last night. Not a lot, but I had to scrape the car windows.

Yesterday, I talked about the trade-off between strong winds and low temperatures. When the lake is ice-covered, wind doesn’t make a lot of difference, so the near-freezing temperatures would win out. But once the lake is about one third open, wind can push the ice around and break it up. I wasn’t sure how this would play out while conditions were so cold, but the wind won.

My first clue was a comment from Minnie, who wrote to say she saw nothing but open water from the south shore. She was down by Morris Point and Warroad. Now you can’t see all that far from the shore, but Josh Broten takes his Cub up to ten thousand feet to get pictures from the US side, and from there, you can see a long way. Here’s what he got this afternoon.

You can click on these pictures to see a full-screen, zoomable version.

Big Traverse

So Minnie was right on. Not a scrap of ice to be seen on the south end of the lake.

Moose Lake

Moose Lake Provincial Park (middle distance) and Birch Point (foreground) are in the Manitoba corner of Lake of the Woods. No ice here, either.

Looking north east from the Northwest Angle

Clipper Island is at the lower left of this shot, Cochrane Island is almost touching the left edge, and Big Narrows is in the distance. That far-off ice is up towards Wiley Point, somewhere around Cintiss Island

Looking northeast  from over Falcon Island.

Beyond Falcon Island lies French Portage Narrows. At the left of the frame, near the wing strut, is Big Narrows. That’s the same patch of ice in the far distance.

 

Shoal Lake

I love this shot of Shoal Lake. There’s still a giant patch of white ice around Dominique and Stevens Islands, but the lake looks to be over half open, not just on the south shore, but also in the northern parts near the Trans-Canada highway.

In case you were wondering, it takes a long time to climb to ten thousand feet in a Cub. Thanks, Josh.

The Aqua and Terra satellites didn’t get a clear look at Lake of the Woods today, but skies cleared enough this afternoon for Aqua to get a partial view.

2020 False colour image from May 3rd. MODIS camera on NASA’s Aqua satellite.

What we can see is all that open water at the south end, and the patch of ice on Shoal Lake at the left. Subtle, but visible, is ice near Hay Island. The part of the lake south of the Barrier Islands is very hard to see. I think there’s some ice there.

Compare this to the clear and sharp image from April 30th.

2020 False colour image from April 30th. MODIS camera on NASA’s Aqua satellite.

Same satellite, same camera, just three days ago!

That’s why this post is titled Tipping Point. Once the ice is more than half gone, it goes suddenly.

However, if it seems cool to you for May, it is. A normal high this time of year is about 15ºC, and an average overnight low would be about 3ºC. Forecast temperatures continue to run cooler than that, with this week getting no warmer than 10ºC and perhaps only reaching  4º on Thursday. Overnight lows could dip as low as -4ºC.

Will we be able to melt the lake with those kinds of temperatures? Yes. But I’m not sure how rapidly. With normal temperatures, I’d expect the remaining ice to be gone in a couple of days, which would put us in the early May bracket, which is pretty common. With this forecast, I’m less sure, but I think we’re on track to do better than the May 14th thaw that Sean and I both predicted just a week ago.

We might be ice free by next weekend. Which is forecast to be cold, by the way. So far, the Weather Network is calling for highs of just six or seven next weekend.

And if that’s not enough to discourage you, remember that Ontario is not moving to lift pandemic restrictions as fast as Manitoba or Quebec, and Premier Doug Ford is flat-out asking out-of-province visitors to stay home. Here’s a link to Kenora Online‘s page with that story.

 

3 thoughts on “May 3, 2020: Tipping Point

  1. You may wish to remind us that water is most dense at 4C. Thus current that brings water from the depths that is warmer than the bottom of the ice is a melter, and once the ice is opening up, aside from wave action, bringing water up from below the 4 C thermocline to the surface has a huge influence on melt.

    Love your posts, thank you.

    Ian Bruce

    >

    • Excellent point, and I had completely overlooked it when thinking about ice melting or eroding when air temperatures are below freezing.

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