I walked the Main Lake of Tonka today from the County Road 15 side. I do not believe the main lake is consistently safe. The depth of the ice varied and there were duck holes, large water spots and pressure cracks. I suggest you say off the main lake.
The ice between Cottagewood and Greenwood, all east of Big Island, appears much better. It has been sailed for the last several days and has received favorable reports. Flyer sailed today and if anyone can find open water it is Flyer (or the Commodore!). Nevertheless, Flyer reports a good of sailing with plates and without incident.
If you sail Tonka on Sat. be sure to scout the ice. The lake recently froze so give the lake the respect it deserves. Even if you think the ice is safe wear your ice picks and NEVER SAIL ALONE.