Roof woes at Tremblay station?

Even though the Confederation Line is having its problems with reliability, I continue to ride. A couple days ago we headed downtown from the Tremblay station. I hadn't been to Tremblay since September, which was only two months ago, but it seems like ages now that the snow and cold have returned. Looking around the station, I saw on its massive, sloping glass roof that many panels have had ice and snow flow stoppers applied. They're those spiky, round sticker-like things you can see in the above photo. They're meant to slow and breakup the flow of ice and snow as it slides down the roof

That photo on the left was shot back in September, and I don't see those snow and ice stoppers.

Maybe the temperature difference between the upper and lower sides of the glass panels allows the snow and ice to melt faster than it normally would, thereby causing little avalanches at the lower end of the roof? Those spiky things would help alleviate that behaviour.

Also, while we were waiting for our train, a workman was up on the roof doing some repairs. It looked like he was caulking some roof panel joints, but your guess is as good as mine.

Winter's a tough season, and it'll be interesting to see how the stations respond.