Did a Massive Ice Disk Really Form in Maine's Presumpscot River?

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Discussion Overview

The discussion centers around the formation of a giant ice disk in the Presumpscot River in Westbrook, Maine, exploring its characteristics, formation processes, and occurrences in other rivers. Participants share observations, personal experiences, and speculative ideas related to ice disks and similar phenomena.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants describe the ice disk as almost perfectly circular and note its rotation, which smooths its edges due to contact with the shore.
  • Others express excitement and curiosity about the ice disk, sharing personal anecdotes related to cold weather experiences.
  • A participant humorously suggests commercializing the ice disk as a ride, while another proposes adding a miniature lunar landing module for novelty.
  • One participant describes the dynamics of the disk's formation, indicating that it is driven by river currents and held in place by fixed ice on the bank.
  • Questions arise regarding the rarity of ice disks on freezing rivers, with some participants sharing their experiences of not having seen similar formations in other rivers.
  • Another participant discusses the conditions necessary for ice disk formation, emphasizing the importance of steady river flow and the presence of eddies.
  • There is mention of floating islands made of vegetation that can rotate, drawing parallels to ice disks but highlighting differences in their formation and movement.
  • Some participants express a desire to find ice disks using satellite imagery, suggesting specific conditions and locations where they might form.

Areas of Agreement / Disagreement

Participants express a mix of curiosity and humor regarding the ice disk phenomenon, but there is no consensus on the frequency of ice disks in other rivers or the specific conditions required for their formation. The discussion remains exploratory and speculative.

Contextual Notes

Participants mention various factors that could influence ice disk formation, such as river flow dynamics, the presence of eddies, and environmental conditions. However, these factors are not fully resolved or agreed upon.

Who May Find This Useful

This discussion may interest those curious about natural phenomena, river dynamics, and the interplay between environmental conditions and ice formation. It may also appeal to individuals interested in the scientific exploration of unusual weather-related events.

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WOW
now that is pretty cool ... in more ways than just one :smile:
 
davenn said:
cool ... in more ways than just one
I first saw this on TV, on the CBS morning news. The reporter doing a standup on the bridge overlooking the disk commented that as a Louisiana boy, he had been looking forward to his first visit to Maine. Then he found out the temperature: 10F (-12C). :eek: He probably had to find a warm coat in a hurry.
 
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So why isn't someone taking advantage of a "green" merry-g-round formed by Mother Nature, putting seats on it and charging $ for the ride of a life time.
Something to tell your grandkids that you rode on the Presumpscot Swirl.
 
I was actually expecting someone to put a little tiny Lunar Landing Module, with a little US flag next to it. And maybe stamp some itsy-bitsy footy prints into the ice.
 
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Btw; does anyone else see a really evil grinning face in there?
 
River flows in from top right, flows out bottom left.
The disk formed in a back eddy and then moves up river until it engages with river flow.
Disk is driven by river current and so rotates counter-clockwise.
Then the curve of the fixed ice on the bank holds it in place.
 
So how common or rare are ice discs on freezing rivers?
How do the major freezing North American rivers do - Saint Lawrence with its upper courses Niagara, Detroit, SS Clair and Mary, Ottawa, Nelson, Mackenzie, Yukon?

Niagara has a steady Whirlpool between the lower rapids - how does this freeze?
 
  • #10
Lived on the St Clair River for over 25 years; never once saw a disc.
 
  • #11
snorkack said:
So how common or rare are ice discs on freezing rivers?
They are rare enough to be interesting. I have seen pictures of smaller disks in a Swedish river. How many processes are there in nature that produce a geometrical wheel?

Disk formation requires a steady flow in the river, with an eddy that can catch and hold free surface ice. If the water flow is such that the water enters the pool on the surface, then sinks down in the eddy to exit deep, then floating ice may not be lost from the eddy and so may build up. If at some level of flow, an eddy collects logs or debris, it will probably be able to form an ice disk. The river level and flow rate needs to be steady, without pulsating waves that might break up the disk or push it over the stationary guides against the bank. For that reason, lower energy rivers are candidates, like the Presumpscot River with little drop, weirs and meanders.

Google Earth History did not show earlier ice disks in that location, but that does not say you won't find them somewhere else. The problem is having a clear sky in winter. Bubbles or scum areas that form in eddies look more like spiral or elliptical galaxies, they certainly do not form geometric circles.
 
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That is an interesting vegetation circle … 34°15'07″S 58°49'47″W, as there appear to be elliptical harmonics present.
BillTre said:
In this case, the mat has to be detached from it surroundings (sides and bottom) and have sufficient current on one side vs. the other to rotate it.
I think in the case of vegetation circles it will not be driven by water currents but by variable winds. I would expect a vegetation disk to roll around inside the outer circle with high peripheral friction, a bit like a cycloidal drive, https://en.wikipedia.org/wiki/Cycloidal_drive

As the vegetation island rotates one way, it's centroid moves in the other sense, not continuously, but only as the wind direction changes. On the other hand, an ice disk appears to be a true circle that rotates continuously about one point, with very low peripheral friction. The radius and centre of rotation may change only slowly as the disk develops, then melts and breaks up.
 
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  • #14
:frown: Don't think I'll be visiting, air fare is over USD $900.
 
  • #15
Tom.G said:
Don't think I'll be visiting, air fare is over USD $900.
Likewise, the photos will have to satisfy me. It should have melted by now.

Has anyone found an ice disk by satellite yet?
Post the latitude, longitude and date here.

Google Earth Pro is free, it has a time slider to view historical images.
Feel the chill in your bones as you look back through the mists of time at the frost and snow.

Search clues. A low energy river with weirs and pools, or with meanders. Maybe in a pool at the bottom of a small waterfall, or at a sharp bend in a river. Also consider bays with sea ice, or bays in lakes that freeze during winter.
I expect ice disks to form during the spring thaw when the river starts to flow again, when surface ice on a pool breaks free from the bank.
 
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