Strawberry Ice Question

Generally, when does the ice at strawberry become unsafe to fish on? We have been having a hard time getting up there, just curious how much longer we have, I know it is still very frozen but when will that start to change?

Here is a picture from April 2 last year at the ladders. There was about 8" of frozen slush on about 8" of clear ice that day. By May 9th here is what the ladders looked like (2nd photo) we were casting out to the edge of the ice from shore. Each year is different but I hope we have through early April again.