April 25, 2018: Rapid Progress

The weather has stayed warm and windy, and it’s making a big difference to the ice. The long-term forecast still anticipates a cool start to May, but for now we’re melting ice while the sun shines.

I’ll start with two pictures taken as we climbed out of Kenora this morning.

That’s Rabbit Lake beside the nose of the aircraft. If you’ve ever wondered why it has that name, compare the shape to a chocolate Easter bunny. It’s distorted by the low angle, and the ears don’t show well, but you can get the idea. Click on this picture to see a larger version that will let you admire the open water stretching all the way from Keewatin Channel at the left to well down the Winnipeg River at the right.

Our second shot looks west down Treaty Island. This picture was hastily taken as we started to turn on course, so naturally I cut off Safety Bay on the right edge and buried Devil’s Gap under the nose. That’s Rogers Island right on our nose, and beyond that you can see water opening up in the Tangle. Still plenty of ice in the Manitou, of course.

Fast forward to our return this afternoon.

This is Whitefish Bay, down by Sioux Narrows, looking west. It’s hazy, and the lighting is flat, so at first I thought all those ripples by the windshield wipers might be open water… but no. Click to zoom in, and you can see cracks in the underlying ice; that’s surface water. Further to the right, there is real open water at Whitefish Narrows, and it has expanded in the last few days.

 

This is Witch Bay in the foreground. Above and to the right are Andrew Bay, Pipestone Bay, Hay Island,  and Bigstone Bay. The ice is much darker, and it looks weak.

Let’s go to the satellite imagery, Bob.

The image above is from yesterday. The image below is from today.

There’s a thin veil of cloud, but that ice looks a whole lot darker. Also, the Rainy River is eating ice at the south end. Falcon Lake and West Hawk look transformed.

To see a comparable natural-colour satellite image with some features labelled, click here or visit the FAQ page.

We’re doing much better than I expected a week ago. Instead of a mild weekend followed by below-normal temperatures, we’ve had several days of average or better warmth, with steady wind and strong sunshine. That could shorten our thaw by a few days.

The long-term outlook is improving, too. While the fourteen day forecast is still calling for a cool start to May, it now talks about returning to normal conditions by the second week, so  although we may still get some cooler weather, it looks as if it could be short-lived.

Will we get set back by a spell of cooler, cloudier weather, or do we dare hope?

 

 

April 24, 2018: Bad Ice

Let’s start with a little drama. I mentioned yesterday that a couple of trucks went through the ice this past weekend. There’s video footage of one sinking at Kenora Online.

A second truck went down in the Clearwater Bay area. Kenora Online has a story and a picture of that, too.

No one was injured in either incident.

We now return to our usual programming. I said yesterday that open water might extend from Safety Bay, on the Kenora waterfront, to Keewatin Channel by today.

So close! Late this afternoon, a few meters of this water passage were still blocked by rotten ice. Click on this picture to zoom in.

I pay careful attention to this area because it goes early and the thaw spreads outward from Keewatin Channel to reach Town Island, Scotty Island and, eventually, the rest of the lake.

Devil’s Gap is making advances in  both directions, and the open water by the Clarion Inn now stretches as far as Bush Island and connects to Safety Bay by the Lake of the Woods District Hospital campus.

A quick technical note. I received a comment from John, drawing my attention to another satellite website, so I’ve added a new link for fans of satellite imagery. The Zoom Earth Link is an interesting alternative to the University of Wisconsin-Madison’s MODIS image site. Zoom Earth is easier to use: there’s just one zoomable image that updates every day. The coolest thing is how easy it is to flip from day to day. (Note: if you zoom in too far, the date option will disappear as change from the satellite picture to an aerial photo from last year!) Another plus is that you can turn on labels for geographic features, and that helps you to get oriented. Downside? No false-colour imagery, and it takes about a day to update, so it lags behind the MODIS images.

If you follow Ice Patrol only by email, you won’t see the sidebar with those links, the comments, or the archives. To use these features, type icepatrol.ca into your browser, or click the link.

Cottage Life interviewed me and  you can click the link to see their article on our late thaw. Maybe this has added to traffic on Ice Patrol, because I notice I’m getting over 2000 hits a day now. It’s been a record year for media coverage.

April 23, 2018: What a Weekend!

It was a warm weekend; at one point we hit 15.7°C, which I think is the first time we’ve seen an above normal temperature since sometime in March. It was also windy, which helps when it comes to melting ice.

At six o’clock this morning, I started my day by heading down to the ice road landing at the Kenora MNR.

This is what it looked like at dawn. The ice at the shoreline was so thin I easily punched through it with my hiking staff. I hear two trucks went through the ice this weekend, but I haven’t had time to look into when or where.

At eight o’clock, I made a hasty appearance at Q-104 to talk about the ice conditions and the effect the warm weather has had.

At nine o’clock, I flew north, and took some pictures on the way out of Kenora.

Airborne off runway 26 and heading west, this is downtown Kenora in the foreground. The picture is roughly centered on Coney Island, with Rat Portage Bay to the left. There is much more open water now, especially in Safety Bay, right of center.

Around two o’clock, we came home again.

This shot shows how much the Winnipeg River has opened up. The main channel has opened up north of the Dalles pretty much all the way through to Minaki.

The satellite images have been showing thin ice at the west end of Clearwater Bay.

Don’t forget you can click on this picture to see the larger, high resolution version, and you can zoom in on that for a better look at Ptarmigan Bay and the far end of Clearwater.

I also wanted to check out the water by the Keewatin Bridge.

There’s just a little rotten ice between Safety Bay and Keewatin Channel now.

Here’s the same area seen from the south as we turned towards the airport.

Looking north at the Keewatin and Norman waterfront. That’s Crowe Island on the wingtip, and I think that passage could be open tomorrow.  If things look a little odd to the right of Gun Club Island, it’s because one of our pesky propeller blades photo-bombed the shot.

All in all, an excellent amount of progress for one weekend. There’s been an encouraging change in the fourteen day forecast at The Weather Network. For next weekend, instead of highs of about 7°C, they’re now calling for 11° on Saturday and 17° on Sunday. I take this as a personal favour, because my sister is visiting from England. Before and after that, though, there’s still talk of below-normal temperatures, and I hate to tell you this, but the first days of May might bring a mix of rain and snow showers.

I hope all these swings will average out and leave us roughly on track.

April 22, 2018: Graphs

I’ve been thinking about how the time it takes to thaw the lake relates to when we start, and how this year fits the pattern. I pestered Sean C. for some data, and plotted it out as a Floating Bar Graph.

Oldest years are at the bottom, newest at the top. Each year gets a bar that starts on the inflection date (when the mean temperature rises above freezing for keeps) and ends on the date when the lake is ice-free.

You can see two kinds of information here:

First thing, there’s some hope that late thaws can go faster than early ones. Compare 2013 to 2012, for instance. It’s not always true, of course; a lot depends on the temperatures and the ice thickness.

Second thing, it looks like we’re having a crummy year. We’re  certainly off to a late start.

I wasn’t sure how to show 2018, because the thaw’s still in progress, but here’s what I did. Inflection date was April 17. We know there’s still ice today, so that first week is dark blue. It would be extraordinary if the lake thawed in under 20 days, so that span is turquoise. I don’t think we’ll live up to the potential for a really fast thaw, because the ice is thick and the temperatures have been at or below normal. The white stretch with the blue outline is my best guess, which is why it ends with a question mark.

Sean sent me another graph of his own. It’s pretty cool, and it does more to look ahead.

This compares 2018 to best and worst recent years, in terms of how fast we reached enough accumulated warmth for a thaw after a winter like this one. That value is represented by the horizontal line at a Thawing Index of 200. That’s our target for this year.

2004 was slow to warm up. That’s the green line staggering along the lower path. I guess we’re lucky we didn’t have super thick ice that year.

2007 was much better. That’s the red line that shoots up steeply.

2018 is represented by the blue dots, and so far, we’ve been following a good path like 2007’s. We’ve risen from a mean temperature just above freezing to seasonal norms in just a few days. But the weather forecast says we won’t be able to keep up that kind of increase, and suggests we might follow a middle road like the yellow line. If we do, we end up ice-free around May 18.

I’ve been pessimistic about the below-normal temperatures in the long-term outlooks, but Sean’s graph suggests that even with the not-so-great forecast we have, we can still be fully thawed for the Victoria Day weekend.

 

 

April 21, 2018: Satellite Retrospective

Let’s take a look at how this year compares to other recent years. Using false-colour satellite imagery will make it really clear how much of Lake of the Woods was open this time each year.

All these images are from the MODIS camera on Nasa’s Aqua satellite, and are used with permission of Liam Gumley, Space Science and Engineering Center, University of Wisconsin-Madison.

The false-colour images give great contrast between open water, which is black, and hard ice, which is turquoise.

To see a natural-colour satellite image with some of the lakes, bays and islands labelled, click here.

In chronological order, starting with 2014:

This is what Lake of the Woods looked like on April 22 of 2014. That was a hard winter that gave us a thaw in late May. Working from top to bottom, you can see little patches of open water on the Winnipeg River at Kenora, The Elbow by Allie Island, Big Narrows, Whitefish Bay near Sioux Narrows, Flag Island at the North West Angle and the mouth of the Rainy River near Baudette.

2015:

This is April 22 of 2015. That was a normal year with a thaw in early May. Quite a difference: nearly half the ice is gone by this date.

2016:

This is April 19 of 2016. More ice area than 2015, but the ice is darker and weaker. The lake still cleared by early May that year.

2017:

April 21 of 2017. The lake is already almost ice free. This was a warm spring following a mild winter.

2018:

This is April 21 of 2018. The focus is a little soft on this one, but you can see how this year closely resembles 2014. I notice two significant differences between this spring and four years ago. On the negative side, 2014 had open water at the mouth of the Rainy River, at the south end of the lake, and we don’t have that this year. On the plus side, the overall quality of the ice looks weaker this year, especially around Clearwater Bay, Whitefish Bay, and south of Big Narrows.

What happens next will depend mainly on the temperature, but day-to-day weather conditions can also have an effect. The ideal sequence would be rain soon, to remove the snow-cover; then warm sunny weather to melt about half the ice; then strong winds to break up the remainder and smash it against the shore. The worst combination would be fresh snow, cold nights and light winds.

So I note with interest that temperatures are likely to sink back below normal after this weekend, and that Thursday could bring us a mix of rain and snow showers. I’d like the rain to dominate.

A late spring can result in a speedy melt if the May temperatures are warm, but I think the coming weather will be more typical of April, so we may not see the ice go very quickly.

I’m still guessing May 15-18 to be completely ice-free, but I’d feel better with an outlook that included more normal temperatures.

If you’re not already there, don’t forget to visit the Lake of the Woods Ice Patrol home page. See all the posts, plus comments, archives and links.

April 20, 2018: Normal Temperatures

Patchy cloud shadows when I landed Friday evening make it a little hard to judge things on this picture. Click on it to see a larger version that makes things clearer.

Rat Portage Bay is in the middle of the photo and downtown Kenora is in the lower right corner. At first glance, it looks as if all the new April ice might be gone, but a closer look shows that nearly half of it survived an afternoon high of 12°C. There are still patches of recently refrozen surface near the Keewatin bridge, in Kenora Bay, and near the Clarion Inn.

But we can take heart in two things: the snow cover is disappearing, and the weekend should be warm. Our forecast for Saturday and Sunday is for temperatures to reach 12 or 13 degrees, which is normal for this time of year. That should finish melting the recently reformed ice and take a heavy toll on the snow cover. It will be mainly sunny, too, so we might finally see some sunshine reach the winter ice. When I go flying again on Tuesday, I hope to see some advances.

The long-term outlook is still not rosy: it looks as if the end of April will still have some overnight lows dipping down to a few degrees below freezing, and the first days of May are forecast to be cooler than normal, too. So although we will make progress, it may not be rapid.

 

April 19, 2018: Factors

I thought if we saw any change today, it would be on the river, where the current is strong. That did seem to be the case north of Minaki, but closer to Kenora, the changes were less dramatic, so just one photograph today.

Here’s a look at the Dalles. That’s Shoal Lake way off in the upper left. For those of you waiting for things to open up around Myrtle Rapids, not yet.

Yesterday I wrote about Sean’s data-based approach to spring versus my observational one. I got some cool feedback in the comments today, so I’m going to put them up here for everyone to see.

First, this one from Stu Everett on whether strong currents help the thaw go faster.

You mention that the analysis does not take a look at current, and how that impacts the length of time from inflection date to ice out. I took a look at the historical outflows from the LOW on the LOW Control Board site. There are some years around the end of March that have relatively high outflows, and others with low outflows. 2016 had very high outflows (most since 2006), and yet the length of time from inflection to ice out was the longest period shown on the graph. Similarly, 2010 was a higher than normal current (outflow) year, yet it too had a long period from inflection to thaw.

This surprises me, my gut feel was that high current flows would quickly show up in the data as a major influence. Apparently that is not the case, at least according to my admittedly brief review of the data.

However, my observation is that this year is shaping up very like 2014. That year, current flows were a bit higher than normal, and actually were on the increase through April. In contrast, current flows this year were lower than average, and have decreased this month. So, if current has any impact, one could speculate that the period from inflection date to ice out will be longer this year than in 2014, if one controlled for other variables. Given that 2014 was about an average year of 32 days, that would suggest that your estimate of less than 4.5 weeks might be a case of “whistling past the graveyard”. But I share your optimism and hope with all my might that my analysis is flawed…

Then a reminder from Matt DeWolfe about the false-colour images available from the MODIS camera on the Aqua satellite.

I find the MODIS Aqua band quite informative for seeing open water, and perhaps ice thickness. Below you can see much of the Winnipeg River open (as well as Rainy River).

https://worldview.earthdata.nasa.gov/?p=geographic&l=MODIS_Aqua_CorrectedReflectance_Bands721,VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),Aqua_Orbit_Asc,AMSR2_Snow_Water_Equivalent(hidden),Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2018-04-18&z=3&v=-96.22655332947613,48.32770514383812,-92.53514707947613,50.26129889383812

[cid:image001.png@01D3D7CE.8B9AF720]

MODIS (Aqua) Corrected Reflectance (Bands 7,2,1)

Temporal Coverage: 3 July 2002 – present

False Color: Red = Band 7, Green = Band 2, Blue = Band 1

This combination is most useful for distinguishing burn scars from naturally low vegetation or bare soil and enhancing floods. This combination can also be used to distinguish snow and ice from clouds. Snow and ice are very reflective in the visible part of the spectrum (Band 1), and absorbent in Bands 2 (near infrared) and 7 (short-wave infrared, or SWIR). Thick ice and snow appear vivid sky blue, while small ice crystals in high-level clouds will also appear blueish, and water clouds will appear white.

Water

Liquid water on the ground appears very dark since it absorbs in the red and the SWIR. Sediments in water appear dark blue. Ice and snow appear as bright turquoise. Clouds comprised of small water droplets scatter light equally in both the visible and the SWIR and will appear white. These clouds are usually lower to the ground and warmer. High and cold clouds are comprised of ice crystals and will appear turquoise.

Today’s Aqua image is a bit blurry, so I’ll use yesterday’s false-colour image to show you what he means.

The open water of the Winnipeg River really pops on this picture, and you can see how the river’s main channel is open far beyond Minaki and Big Sand Lake all the way up through Umfreville Lake and beyond. The rusty-looking patch near the south end of the river is Kenora, and the two patches of dark water near it are Safety Bay and Keewatin Channel. The wishbone-shaped patch of open water near the center of the picture is Big Narrows, and the tiny dark patch halfway down the right side is Whitefish Narrows. If you need more help figuring out what you’re looking at, head over to my FAQ page, then scroll down to the bottom to see a natural-colour image with some of the key features on and around Lake of the Woods labelled.