you just never know

[smokepoles]

Dang, Chuck I'm glad you didn't go all the way under! Be safe out there bud. I rarely ice fish past V-Day for that reason, the ice integrity softens up a bit in late winter.

The ice itself was great where we fished.  We were at least a couple hundred yards from the inlet open water, and on the far side of where others had went, but can't help but think from the flow of water I observed that a water stream finding its way from the open inlet over the ice.    I have indeed in the past observed holes that do not appear to be from drilling, and those to to the east (inlet) of where we normally go in from the south dike between the no parking signs.

The weak spot you found is all because of the methane venting from decomposing underwater plants. They do it all Winter long but when it is really cold they freeze over and you can walk right over them and never know it but as soon as a little warm weather hits, those are the first spots to thaw out because the methane has weakened the ice so much. The first time it happened to me there I thought it was because someone used a 10" augar but as you said the hole wasn't even, in size.

Yeah, I wonder if those methane vents tend to find their way to a previously drilled hole, then come up through the hole and spread out horizontally creating a layer of water between thin shelves of ice?  As I said, there sure seemed to be a unexpectedly large flow of water back down into where I pulled my foot out.   I don't expect its more than 5-6 feet deep where we I broke trough, and that probably plays into it all. 

Thanks all for sharing your wisdom.