Dec 162016
 

Upon waking up on December 5, there were eight white, fluffy circles in the ice on the pond adjacent to our house. At 10:00 am, I snapped the first two photos. Now it’s 2:30 pm and I am home to a melting scene but as you can see the circles are holding. I find it so fascinating. The water level in the pond and the lake is very high for this time of year. Any ideas to solve the mystery?

Sandra Burri, Kawartha Park

Ice circles on pond at Kawartha Park on Clear Lake - Sandra Burri - December 5, 2016

Ice circles on pond at Kawartha Park on Clear Lake – Sandra Burri – December 5, 2016

Ice circles at Burri's pond - Kawartha Park - December 5, 2016 - Sandra Burri

Ice circles at Burri’s pond – Kawartha Park – December 5, 2016 – Sandra Burri

NOTE: Here’s a theory from Sandra’s husband, Dick, as to how these circles formed. “As you know the pond is spring fed and also receives run-off water from the road and the hill. When a thin surface of ice was formed on the pond, the additional spring fed water created some pressure under the ice surface causing the ice surface to rise. Lets assume that the ice surface at the periphery of the pond was held down as a result of being locked into the ground. That would result in the ice surface being forced into a concave shape to accommodate the added volume of water. As the pressure rises under the ice, at some point a hole would be blown in the ice sheet to reduce the pressure. I think the first blowout would be the biggest because the ice thickness would be the thickest at that time, resulting in the largest circle around the hole and the largest amount of water release from below the ice level. Subsequent blowouts would be less violent (because the ice thickness at the original breakthrough would be significantly thinner and as a result requiring less pressure to break through), with less water outflow resulting in smaller circles. Today I counted more than 20 circles on the ice. I also think that the recent heavy rains that we have had resulted in high ground water levels and that the under water springs (in the pond) were able to create sufficient pressure under the ice. I had always heard that the pond was spring fed – maybe this proves it??  And that’s my theory.  Dick Burri

 

UPDATE: For your information, we drove up to Apsley on Dec 4 and there were several ponds off of the highway, on both sides, with ice circles in them. We didn’t stop because of the traffic and I mentioned them to Sandra. We had never seen them either, but a spectacular view none the less.
Barb Rimmer, Peterborough