We have entered the micro-season of “The Spring Water Holds Warmth”, which is the second part of the mini season of Minor Cold.
Minor Cold, which will be followed by the mini season Major Cold, is the fifth of the six mini seasons of winter. The micro-seasons contained within this mini season are:
- The Water Dropwort Flourishes (Jan 06 – Jan10)
- The Spring Water Holds Warmth (Jan 11 0 Jan 15)
- The Pheasant First Calls (Jan 16 – Jan 20)
The micro-seasons were established in 1685 by Japanese astronomer Shibuka Shunkai. Each micro-season lasts about five days and highlights a slight change in the natural environment. The micro-seasons are specific to the climate of Japan as they were developed around their agrarian society. However, just because the calendar focuses on Japan doesn’t mean that it isn’t applicable to others. They can become a starting point for a personal exploration into the world around you.
The Spring Water Holds Warmth
As a young person growing up in the Northeast, January was usually the time that we started thinking about ice fishing and pond hockey. As we started sharpening our skates for the season, we were also reminded of the dangers of thin ice. This micro-season, “Spring Water Holds Warmth”, could be seen as a reminder about the variable factors that play into ice thickness.
The general rule of thumb is to stay off ice that is less than 4 inches thick. The only good way to know the thickness of ice is to drill several test holes and measure it. With that said, there is a formula that can be used to estimate the freezing rate of ice.
Calculating Freezing Degree Days.
Much like calculating out wind chill factors, there is a formula that you can use to determine the rate at which the ice accumulates on a pond or lake. You begin by calculating the average temperature of the day by adding low temperature and high temperature and dividing by 2. (Use degrees Fahrenheit.) Now subtract that average from 32 degrees, the temperature at which water freezes. You have now just calculated what they call “freezing degree days.”
Freezing degree days will add 1 inch of ice for every 15 freezing degree days in a 24 hour period. The only caveat to this formula is that there must be a thin layer of ice on the surface before this formula works.
Mike Szydlowski, Columbia Public Schools’ Science Coordinator, provides us with a narrative of how this works.
“If the low temperature today was 24 degrees and the high was 30 degrees, the average temperature of the day was 27 degrees. Subtract that from 32, and you get 5 freezing degree days for this day. . . . If we had a day with 5 freezing degree days, you would use the formula 5/15 = .33. On this day you would add .33 inches of ice, or 1/3 of an inch. But remember, this is after the first layer of ice forms.” (1)
For those who are more visual learners, The graph below provides another representation of how this formula works.
It should be remembered that there are a lot of variables that come into ice formation. So these formulas and graphs should only be used as a way to estimate thickness. You should always test the ice before you go out on it and physically measure the thickness to determine its safety. Another important caveat to this formula is that it is only for lakes and ponds. In other words, it is just for water that is relatively still.
So how might spring water, or moving water, play into this formula?
Does spring water freeze?
An interesting thing about spring water is that it is moving water. As a result, it doesn’t necessarily freeze over at the same time as pond or lake water. The scientist at UC Santa Barbara explain this process by stating;
‘For flowing water to freeze, the surrounding air has to be colder than 32°F, because the flowing water mixes with itself. So, the colder water on the surface mixes with the warmer water from the bottom, and the average temperature is somewhere between the two. . . Also, the motion of the water can cause heating. For example, water in a waterfall gains kinetic energy as it falls, which is converted into heat and sound energy at the bottom. Therefore, the surrounding air temperature would have to be lower to force the water in the waterfall to cool to 32°F and freeze.”(2)
Another thing to consider is that spring water emerges from below ground where it is warmer than the surface temperatures. In Vermont, where the winters are fairly cold, the frost line is estimated to be 5 feet down. What that means is that once you get below 5 feet in the ground, the ground temperature stays above freezing. So when we think about spring water holding its warmth, we are perhaps talking about how the spring water is resistant to freezing because it emerges from below the frost line.
Although, this warmer water can slow down the freezing process, it will not completely prevent it. It just takes many days of really cold temperatures for this water to freeze over. Also, because rivers and springs don’t freeze at the same consistency as ponds or lakes, care should always be taken when walking on frozen rivers and other places with moving water.
Some Haiku About This Season
And, because we can’t close a post without some poetry. I have found a few haiku about ice.
this ice tastes bitter – enough for a rat to wet his throat -Matsuo Basho
Little pieces of ice in the moonlight Snow, thousands of em -Jack Kerouac
Water in the birdbath - a film of ice On the moon -Kerouac
America: fishing licenses the license To meditate -Kerouac
This last haiku by Kerouac isn’t necessarily about ice. But when I think about fishing, I tend to think about ice fishing.
You can read more poetry about snow and ice here.
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I really enjoyed this post on the mechanics and beauty of ice, Mark. Your background in cold winters and how to measure ice was interesting, and I really like your lessons on the micro seasons. Although I live in Calif. and the seasons are different than Japan, your micro seasons talk always gets me thinking about our micro seasons. Great post.
Hi Jet, Thanks for the comment and I am glad you enjoyed this. I spent about a year and San Diego and quickly realized that a missed the seasonal changes of the Northeast. I have also noticed, as I continue down this path, how much more fascinating the cold winter is! For example, tomorrow the wind chill is suppose to be -30. That is amazing! And, kind of intense. Talk soon,
Basho and Jack K – Awesome!
Hi Phil, I went on a Jack Kerouac dive the other day. I received an email about how he would have been 100 in March and this led me down a path of Kerouac haiku.
Hi Mark. I had his book of haiku, which I somehow misplaced. I have to get my hands on another copy. I like his contemporary description of haiku as a 3 line poem! Gives alot of flexibility!
Confession: I skipped past the math and went to the haikus. 🙂
I totally understand!
This is fascinating and, of course, brings back memories of frozen farm ponds in my youth. Our cow ponds were small and shallow so there really wasn’t a lot of danger if the ice broke. I recall several occasions where I’d shovel the foot or two of snow off the ice so I could try to ice skate. On one occasion, I was exhausted from shoveling and skating so I laid down on the ice and closed my eyes. I must have dozed off for a few minutes because when I opened my eyes, there were about a dozen cows standing mere feet from me, just staring at me! It was shocking and hilarious. I had no idea what was going through their minds–they probably thought I was dead. Oh well. Overall, even though we had some bitter cold days and nights at 7,000 feet elevation, many winters we didn’t get enough of those cold days/nights to freeze the ponds sufficiently for skating. I always felt envious of folks who got to play pond hockey and ice skate a lot during the winter. And of course, frozen ponds meant taking an axe to them every morning to chop holes for the cows and horses to drink. Great job as always, Mark. Stay warm in that -30F wind chill! 🙂
Hi Mike, What a great description of winter life on a farm! I remember shoveling the snow off the pond in order to create a hockey rink. My neighbor built, what I remember as, a giant shovel that worked like a snow plow. He would put his skates on and push this thing back and forth across the ice. He used it as his strength training. Kind of like people do now with pushing weighted sleds or pulling chains. You know, a normal day on the farm. Glad you enjoyed this post. Talk soon,