CSI: Lake Monona Edition – Open Water in Negative Temps?

Ice boating is probably not advisable under Lake Monona's current conditions. Unless you're wearing a life jacket! Photo: Jeff Miller, UW Communications
Ice boating is probably not advisable under Lake Monona’s current conditions – unless you’re wearing a life jacket! Photo: Jeff Miller, UW Communications

Over here at the CFL, all the talk has been about the ice covering Lake Mendota. That’s all well and good, but it’s diverted attention from something happening on the other side of the isthmus – Lake Monona is refusing to freeze.
UPDATE: Matt Schwei reports that, ow that the temps have moved to being a bit more moderate, Lake Monona’s open water has frozen over. Go figure. The best guess from folks at the CFL is that currents in Lake Monona were pushing the warmer water at the bottom of the lake up near the surface and keeping things just warn enough to keep from freeezing. Maybe we’ll hire a grad student to get to the bottom of this!
At this very moment, a huge swatch of the western waters of Lake Monona are rippling in the wind. This despite the fact that the last few days have seen high temps of 16, 11 and 8 degrees Fahrenheit and lows all well below zero. While we know Mendota’s late freezes are correlated with higher average temperatures, explaining Monona’s capriciousness is a bit trickier. (It should be noted that open patches of water don’t mean a lake’s not considered frozen – for more, check out the state climatologist site)
Despite consistent sub-zero temperatures, Lake Monona's ice cover is having a variably winter. Photo: Matt Schwei
Despite consistent sub-zero temperatures, Lake Monona’s ice cover is having a variable winter. Photo: Matt Schwei

Yesterday we received the above picture from blog follower, Matt Schwei, whose office has a view of the perplexing display. His questions were forwarded on to our resident ice expert and director emeritus, John Magnuson. Here’s what John wrote back, with the caveat that he hasn’t been out to observe the phenomenon himself:
“A few things to think about and check on. One is the possibility of warm water entering from MG&E — their outfall is a little east of the Convention Center. Two is that there may be some salty water moving around from the salt on the streets after the last big snow fall. Three, the sun is getting higher in the sky and has more heat per square foot than when the sun was lower in the sky. Four is the wind in the right direction that it could be moving the ice to the south or south west as it is often unattached to the shore around MG&E.  Wind driven currents could also be playing a role.”
Ted Bier, the senior research specialist for the CFL’s Long Term Ecological Research program says, whatever it is, the year isn’t necessarily unique. “I have a picture from winter sampling one year where I’m drilling a hole in 22 inch ice and, a hundred yards away, there’s open water [on Lake Monona]” he says.
The patch of open water extends from Monona Terrace neary to the John Nolen bridge. Photo: Matt Schwei
The patch of open water extends from Monona Terrace nearly to the John Nolen bridge. Photo: Matt Schwei

Whatever’s going on in Lake Monona, we’ll keep picking the brains of our researchers and provide updates if we think we’ve got the answer. Stay tuned…

3 thoughts on “CSI: Lake Monona Edition – Open Water in Negative Temps?”

  1. On Monday 21 January, a correspondent in Shorewood Hills reported a huge open area on Lake Mendota, roughly between Fox Bluff and Shorewood Hills. Even though Mendota froze by the technical definition on 14 January, it was still partly open a week later.

  2. I made an unfortunate driving mistake while on John Nolan Dr recently. Suffice it to say – please keep your eye on the road while driving here – if the lake is so interesting (and we all know it is), park and walk to get a good view!

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