At some point, the ice was a continuous mass that was just starting to build candles. This means that it is not safe to walk on, since the ice will break with no warning. Our dry suits (thank you Kokatat!) were a big help when we were tracking the canoe over the ice for one day. With the dry suits, we were able to track fast over the candeling ice. If one of us would break through, he could climb on the ice in no time and we could proceed tracking.
However, this is not recommended technique and asks for considerable experience with spring ice conditions!