I mean, it was enough for a loon to get on and off of for sure, but a lot of the lake was still frozen. Ted was right, as this week's migration map shows. The Lake Monona loon was reported on March 19. This isn't an exceptionally early date, but there WAS something exceptional about this sighting. Loons almost always wait for a lake to be mostly or even entirely open before they land.
Loons are large, heavy birds that have small wings.
The only way loons can get their heavy bodies into the air is to run straight into the wind on the water's surface, flapping their wings as fast as they can. Of course, in springtime the water is likely to become more open day after day, so this loon wasn't in serious trouble as it waited for more open water in other places. Lakes might be frozen and they couldn't land or find food. Risking the worst weather of spring, including blizzards, ice storms, and tornados. Eggs and chicks can be lost from other things, too, especially predators.