Most of the lakes commonly used by divers up here in the "Great White North" are still wide open. A little chilly, and the air temp is hovering just above or below freezing temps, depending on the day. But If your hardy (make that fool-hardy) and have a good wet suit, or realistic and have a dry suit. This time of year is just about the best. Visibility is well over 100 feet, no algae, no students stirring up the bottom, no boats, in short its perfect.
As for diving under the ice, the vis is even better due to the lack of wave action stirring up the water. On the down side, you are in one heck of a large overhead environment. Even though you have great visibility, you can still end up loosing your way back and end up dead. That is why we always use a safety tether, surface support to manage the line, and safety divers to go in on a moments notice to locate you if you fail to respond and the line cannot be pulled in. I have seen people on this board ponder the question of whether or not ice diving is technical diving, or just recreational diving. My answer to that is simply it is both. We dive under the ice for recreation, but must follow strict guidelines and protocols far in excess of what open water diving requires in order to ensure a safe weekend of fun.
