There are times that the entrances to the glacier areas are so blocked by ice that the ship can't safely enter.
Also, there are days where the fog is so thick that the ship either shouldn't enter, or you can't see a thing if the ship does.
There was a time, several decades ago, where the entrance to Yakutat Bay was so clogged with ice that there were whales stranded in the bay, and were in danger of dying. Fortunately, the ice dam broke in time for them to escape.
My first time at College Fjord, I really couldn't see a thing, due to the fog. On one visit to Sawyer Glacier up Tracy Arm, we couldn't even get close to the glacier. Nice enough day, but so much ice that the glacier was around a corner, and there was no sighting.
You can see plenty of ice and snow in Alaska, but it doesn't necessarily have to be in glacier form.