Micro-Season: “The Mountain Stream Freezes Over”

We have entered the micro-season of “The Mountain Stream Freezes Over”. This is the second micro-season of the mini-season Major Cold.  All the micro-seasons within Major Cold are:

• The Giant Butterbur Flowers (Jan. 21 – Jan 24)
• The Mountain Stream Freezes Over (Jan 25 – Jan 29)
• The Chicken Lays Her First Eggs (Jan 30 – Feb 03)

These seasons were established in 1685 by Japanese astronomer Shibukawa Shunkai and are specific to Japan. However, just because the calendar focuses on Japan doesn’t mean it isn’t applicable to others.  No matter where you live you can use these seasons as a starting point for your personal exploration of the world around you. 

To celebrate this season, we will learn about what it takes for moving water to freeze, and then read haiku by Basho, Issa, and Shiki..

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A Frozen Mountain Stream

All water will freeze when it reaches 32 ℉ (0 ℃). However, flowing water, such as water in rivers and streams, will freeze at a slower rate than standing water, like water in ponds or lakes. The scientists at UC Santa Barbara explain this concept 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.”⁽¹⁾

So, for flowing water to freeze, it needs to be significantly colder than 32 ℉ for a considerable amount of time in order to facilitate the drop in water’s temperature below freezing.  This is why your neighborhood pond might be frozen but the river that runs through the town is not.

Now let’s take a closer look at two of the factors that influence how quickly flowing water freezes.    

The Source Of Water 

As we learned in “The Springwater Holds Its Warmth”, spring water is stored in underground aquifers and the temperature underground is warmer than the temperature above ground.   In Vermont, where the winters are pretty cold, the frost line is estimated to be 5 feet down.  That means that once you get below 5 feet down, the temperature stays above freezing.  Therefore, even if the spring water is not considered a “hot spring” the water that comes to the surface from an aquifer will be below freezing and will mix with the surface water reducing heat loss. 

How Fast Is The Stream Moving?

As the scientists at UC Santa Barbara said, movement produces kinetic energy. The faster the water is moving the more kinetic energy it will have. This will then create heat and slow down the rate at which the water can freeze.  A simple way to see this concept in action is to compare a slow-moving brook to a faster-moving mountain waterfall.  While the temperature around a mountain waterfall and a mountain brook might be the same, the brook will usually freeze faster.  Walter H. Smith, Associate Professor of Biology at The University of Virginia puts it this way:

 “In reality, freezing becomes a close dance between air temperatures and streamflow. The cooler the temperatures and the slower the flow, the more quickly a stream will freeze.”⁽²⁾

A Note About Ice Safety

Although it can be fun to walk on a frozen lake or river, it can also be dangerous. A general rule is that 4 inches or more of ice is safe to walk on.  Any less than that poses a safety risk. Also, ice that forms over rivers and streams can vary greatly in its thickness so extra care should be taken when crossing these waterways. 

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Seasonal Haiku

According to the World Kigo Database, Ice (koori) is a late winter kigo.  However, there are some variations of ice that make it a kigo for other seasons.  For example, First Ice is a mid-winter kigo.  Whereas, thin ice, melting ice, or floating ice are spring kigo.

With all this in mind, let’s read some frozen haiku.

Basho

awakened at midnight
by the sound of the water jar
cracking from the ice
(translated by Sam Hamill)

ice is bitter
in the mouth of the rat
quenching its thirst. 
(translated by David Landis Barnhill)

drawing water, 
ice-covered monks’ 
shoes make a racket! 
(translated by Thomas McAuley)

Issa

the ice of the moat
cracking...
winter moon
(translated by David G Lanoue)

night wind--
the shrine's icicles
reflect the lights
(translated by David G Lanoue)

on honorable Buddha's
honorable nose
an icicle
(translated by David G Lanoue)

Shiki

one spoonful
of ice cream brings me
back to life
(translated by Tanaka Kimiyo)

A Haiku Invitation

This week’s haiku invitation is to write a haiku or senryu that references frozen water in any form. You may want to write about the icicles that form on the eaves of the house, the ice on your car’s windshield, or even ice fishing.

Share your haiku in the comments below, or post on your own page and link back to this post. I can’t wait to read what you write!  

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References:

1. UCSB Science Line; Question Forum
2. Smith, Watler H. “Why Do Streams Not Freeze In Winter”. Appalachian Biodiversity and Society Lab
3. “Adirondack Lake Ice Safety” Ausable River Association
4. Ice (koori). World Kigo Database

Basho’s haiku were retrieved from “Matsuo Bashō’s haiku poems in romanized Japanese with English translations” Editor: Gábor Terebess.  Issa’s haiku were retrieved from David G. Lanoue’s Haiku Guy. Shiki’s haiku was retrieved from Terebess Asia Online