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.

10 thoughts on “April 19, 2018: Factors

  1. Hey there, I’m new to this site and I gotta say I love all the info, it’s super interesting to read. I live in Kansas City Missouri and come up every year to Fish. This year we are going to Red Lake, which is considerably farther north, we are supposed to be up on May 25th this year. I can’t find any info out about ice out, does anyone know of any info for what they might be looking at as far as ice out/conditions?

  2. I love the Satellite image. Please post daily. Or every other day if it’s too much trouble.

    • Sometimes the pictures are blurred, and sometimes clouds hide the surface. I update the link whenever whenever one of the satellites gets a clear shot, but you can use it to visit the University of Wisconsin site, and select different dates yourself. The shot from the 20th is marginal, with thin cloud.

      • Perfect, thank you for all the work you put into this. Sure hoping the ice is off for opener.

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