See my posts in the Southern Keweenaw Update thread....
Edit: Just read the OP closer, and feel I should provide some additional information. I in no way claim to be an expert on the ice conditions of the canal and Portage Lake, but can only relay the bits of information I've picked up over the years.
Maybe unnecessary, but let me first point out the difference in terms between Portage Canal and Portage Lake. Portage Lake is the lake southeast of Houghton, stretching towards Chassell. Befor people came to the Copper Country, this lake extended close to the current downtown of Houghton, but was not connected in any way to Lake Superior to the NW. Back in the 1860s, a canal was dug from the historic NW corner of Portage Lake to Lake Superior.
My understanding is that the area of the canal "near" the bridge is the worst, to the point where the ice there should never be trusted. Part of this is due to the direct area under the bridge having salt fall from the road. I've also heard the water currents there are especially bad due the canal being narrow in that spot. Therefore, I've personally never ridden anywhere near the bridge, even where so many people cross from Chutes and Ladders to the Ramada. However, yesterday when I was down by the canal there were hundreds of tracks getting off/on the ice near the bridge heading east.
In my first couple years at Michigan Tech I would routinely cross over northeast to the spot where there is an opening for a gas/pipe line with trail 3 right there running along M26 ( the area cleared for the line can easily be seen on satellite imagery). For my comfort levels (not exactly the biggest fan of ice riding myself) I felt far enough away from the narrow area near the bridge and on an area that was naturally part of Portage Lake. Yesterday, my parents and I rode Portage Lake from Chassell to that same line opening across from Michigan Tech, and everything was smooth and solid (no areas of slush even with the recent warm up). I have read that the area where Pilgrim River empties into Portage Lake is sometimes a bad spot due to the incoming currents, but we did not see any sign of that yesterday.
