The portage course is definitely not completely flat and I'm not sure it was flat. I ran at Portage today in the D1 Men's Varsity race (The same one that Fisher ran in).
*****If you're wondering how the Portage course is laid out*******
***The first 0-2000 meters of the race are almost constant up and down hills.
***2000-3000 meters of the race has an extremely flat area that loops around back to the start.
*3000-4000 goes over some of the same hills that you experience in the first 2000 meters.
***4000-5000 meters goes back to the same area as the 2000m mark, and has one of the flattest finishes to a race I've ever seen. It's actually incredibly exciting. My time was only around 17:05 and I had a 3 minute final thousand meters.
***There is a huge hill that you go over twice. Once about 400m into the race, and again around 3000m into the race.
***My gps watch read the course at 3.10 miles. Normally it reads courses around 3.09-3.13 (depending on a number of things) so it seems like a pretty accurate course.
I'd say it is slightly easier than most courses, but certainly not a pancake. If you're wondering the temperature for the day, it was amazing conditions. The temperature was around 47 degrees and cloudy (but no rain for hours before the race). It was a bit windy (maybe 10mph winds), but the wind seemed to have died a bit during our race.
It did feel extremely cold after we had run the race, but the temperatures during the race didn't seem too bad, and everyone on my team ran a PR.