Unusual Early Season Lake Ice Formation

Observation by Gillian Brubaker:

I was walking around Cheney Lake on Halloween and noticed these unusual ice formations. There were three rings in the middle of the lake which were all about 30 feet in circumference. I have lived here for almost 60 years and I have never seen the ice form like this before. I talked with my friend Glen and he said it might be caused by methane. We were unable to go out to see if there were any bubbles. I know there are artesian wells at the north end of the lake, but I am not aware of any located in the middle. The ice had only just formed when my friend Gwenn Kennedy took these pictures. What causes this ice formation? Does this effect the strength of the ice? I am a little worried about people walking on the ice.

Comment by LEO Network Editors:

This observation was shared with our friends at the Alaska River Forecast Center for a consultation. LEO Network invites LEO Network members to share their comments on this observation.

Johnse Ostman with NOAA writes:

I found discussions regarding "ice circle" formation and occurrence described in a few places. None of those references specifically describe the formation on lakes right at freeze-up but after an ice layer already exists, although they have been observed on rivers at freeze up. Theoretically these ice circles are formed from water movement and temperature differences between the "disc water", i.e. water within the circle, and the surrounding water due to eddy formation where the "edges" erode (from rotational shear) and form a circle. A few questions I would have to research answers for are: Is Cheney Lake only GW fed, i.e. no inlet or outlet, so how would the flow component, albeit very low flow, be achieved here? Is Cheney Lake really shallow? Could there be groundwater upwelling which causes the necessary water temp difference as ambient air temp drops, and maybe that velocity difference to produce the gyre? I also found that Methane seeps can create a rising mass of warm water that begins swirling in a circular pattern (i.e.Coriolis force) and once that (warm) water mass reaches the underside of the ice on the surface of the lake, it melts the ice in a ring shape. So more questions: Was there an old stump dump or similar at Cheney Lake when those east side neighborhoods were developed? What other sources of Methane could exist beneath Cheney Lake to produce an upwelling? 11-15-21

LEO Editor Mike Brubaker writes:

Wow this is turning into a really interesting discussion. Thank you so much for your consult on this post. What I know about the Cheney Lake is that it was a originally (1960s) a gravel pit until springs at the north end became to productive and flooded the pit. It also has a lot of homes along the east side that I think are up gradient and on septic tanks. I don’t know anything about dumps, but who knows what was buried at the bottom of a gravel pit.