Persistent Hazard Map

Screen capture of the Persistent Ice Hazard map around the Champlain Bridge.  

Some types of hazards occur in the same place year after year.  Gas, current and reef holes are good examples.  We have started a map which has a fair amount of data for some parts of Lake Champlain. The map is most useful for checking out an area to learn of some of the problems you might find there.  As always, expect to find hazards not shown on the map.

 Click here to go to the Persistent Hazard Map page for more information and a link to the map itself.


What a Difference Cold Weather Makes


Christmas Day on Squam Lake, New Hampshire.  Photo by Randy rice

We have had a great start to the 2014 ice season.  Comparing average November+December temperatures for this and last year in the East and Mid-western parts of the ice belt, we are averaging about 6 degrees colder this year and more like 8 degrees for December only. 


Graphs and data from

The December temperature history for Burlington (VT) is typical of what occurred across the ice belt.  Days with temps over 45 degrees are hard on new ice.  We had five in December last year and one this year.

So far, November and December have had 60% fewer bad ice accidents than we had in the same two months last year.  There is no doubt in my mind that much of that improvement is related to colder temperatures and a lot less ice being weakened by warm spells.





Blue Ice

We had some spectacular colors on one of our local ponds this past week.  

An explanation of the above picture from top to bottom: 


  • The dark stuff is 3 day old (Nov 29) black ice at the edge of a frozen new-ice hole
  • The green band is bio-skuz (my term) that accumulated on the down wind end of the hole before it froze. The pond is heavily infested with aquatic plants. 
  • The white stuff is a 1/4" layer of snow ice that fell as snow 5 days ago (Nov 27) on black ice that came in 7 days ago (Nov 25). 
  • The blue is (as explained below) pigments from cyanobacteria that have died and released their blue pigments into the water.  They are soluble in water and were carried by the water as it infiltrated the snow while it fell 5 days ago. 
  • The black object at the bottom is the front third of my shoe (for scale).
  • Note:  The picture was taken on December 2, 2013


A friend, Tom Vogelmann, is a botanist with consideragle expertise in photosynthesis who has also studied algae in snow.  I sent him the above picture with my speculation on what might be going on.  His comments:

That's a great photo and I have never seen this phenomenon in the wild.  But of course I don't hang out at the edge of developing ice sheets either.  The blue is most certainly pigment from cyanobacterial cells that have been broken apart by freezing.  Most cyanobacteria contain two intensely blue pigments, phycocyanin and allophycocyanin.  Sometimes they contain a third pink pigment called phycoerythrin.  They are all proteins that are closely associated with the photosynthetic membranes and their role is to capture light at wavelengths that are weakly absorbed by chlorophyll, and transfer the energy to chlorophyll via resonance transfer (99% efficiency).  These pigments, when released from the cells, are also highly fluorescent so if you have a hand-held UV lamp, you can make them light up.  Fun stuff.

In a follow up conversation I asked Tom about how the blue pigment could get out of the cells other than by freezing as it seems unlikely that the 'ice edge bio-skuz' froze before the pigment became mixed with pond water which was then wicked into the snow that fell on the 27th.  He pointed out that abrasion by wave jostled snow/ice chunks mixed with the cyanobacteria might be sufficient.  Another possibility is the cyanobacteria may die at above freezing temperatures if the lipids in the membranes get too stiff (he use the example of a banana turning black in the refrigerator).

A third possibility is that cell death occurred before accumulation at the ice edge and the ice edge jostling broke up the dead cells to release the pigments. 


Blue stain in snow ice around a wave-break crack about 40 feet from a frozen ice edge in the older ice.  

 Looking along another crack about 100 ft from the frozen ice edge. 

This  photo is looking through a 1" thick vertical section cut out of the green band.  It is illuminated by a light table underneath the ice block.   The dark green items are plant bits.  On the tops of some of them the bluish pigments appear to have made their way upward through the pore structure that existed when the ice was thawed ( 11/27or 12/6).  The image is about an inch wide.   

We had a windy warm spell after these pictures were taken and the snow ice layer was zambonied off the ice sheet.  



Finally, an Early Ice Year


Dolloff Pond, Conway NH. 4" of ice.  Nov 29, 2013  Mt Washington in the distance.  Photo by Lee Spiller.


 Every 10 years or so we have ice by late November in northwestern Vermont. This is one of those years.  Even with things generally warming up it is nice to see we can still get some proper cold weather now and again.  

Shelburne Pond, Shelburne VT. Nov 29.   The grey ice in the foreground is about 2.5".  The black ice further out needs at least one more cold night. 


First 2014 Ice Season Blog Post

Photo by Karl van der Voort

Welcome to the 2014 Ice Season! 

Over the summer we have been working on several articles.


  • A review of accidents from the 2013 season looks at the ground truth of why people die on ice.  The summary page in particular is important reading.   
  • One result of that report was understanding  how much of a role thawed ice plays in accidents. (more on thawed ice)
  • Ice on rivers behaves differently than ice on lakes.  They can offer an interesting ice venue but also have several new ways to get in trouble. (more on Rivers)
  • If you missed it in April, where were  several spectacular ice push events on Lake Champlain, and Winnebago (WI) and Mille Lacs (MN) and Dauphin Lake (MAN).   
  • A write up for an unusual large scale ice formation in Newfoundland in March. For a while it was thought to be something that fell from above. 
  • Rip-outs are a reasonably common source of large areas of  open water that form after the ice had come in.  This article is based on a picture taken by the NH Civil Air Patrol over lake Winnipesaukee. 
  • Karl van der Voort sent some pictures showing some of the signs of ice getting toward being significantly weakened by thawing.  He also sent a few more pictures from his skating adventures. Karl found great skating ice in Northern Sweden in late October.  The pictures on this post were taken by Karl on his trip. 







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