3 min read

Singing Ice

The Sound of Acoustic Dispersion
David Lukas recording
Recording singing ice this morning. Photo by David Lukas

This newsletter is about curiosity and engagement, and today was a perfect example of why I love writing these newsletters.

I also love writing these newsletters for you, and I am thankful for the support of the many followers who look forward to them every week. If you want to help, please consider signing up for a paid subscription, or make a donation in any amount with the link below.

This morning, I was all set to spend the day at my desk, writing about the separation between plants and animals. My office was warmed up, my cup of coffee had just finished brewing, and I was ready to sit down.

David Lukas at his desk
Working on today's newsletter. Photo by David Lukas

Then I stepped outside to bask in the sun for a moment...and discovered that the lake in front of our house was singing!

ice-covered lake
Covered in ice and singing! Photo by David Lukas

This was too good of a moment to pass up. It was the best singing I've ever heard from our house, so I dropped everything, packed up some gear, and instead of working on the newsletter I spent three hours visiting different ice-covered lakes to discover what was going on.

David Lukas recording
The ice is much thinner now, so I'm sticking close to the shoreline. Photo by David Lukas

If you've never heard singing ice, it's one of nature's most haunting acoustic experiences. The sounds have been compared to seals blowing bubbles in echo chambers, to Star Wars lasers, and to the sharp cracking of whips. It's all those things, and so much more.

Jonna Jinton has one of the best examples of singing ice on YouTube.

These sounds are created as sheets of ice covering lakes expand and contract due to changing temperatures. The sounds are best heard in the fall and spring (hence today's sounds), because this is when temperatures change most dramatically between cold nights (temperatures were in the 20s last night) and warm days (today is a sunny warm day).

moose poop on ice
Moose poop on an ice-covered lake. Photo by David Lukas

As ice expands and contracts, it creates stress that the ice releases by cracking and shifting. These sudden movements produce an otherworldly range of sounds including groans, squeals, chirps, and explosive pops.

ice texture
Complexly cracking and shifting ice. Photo by David Lukas

Water is an excellent transmitter of sound waves, so these sounds move extremely fast across the lake resulting in a phenomenon called acoustic dispersion. Essentially, different frequencies travel at different speeds and, given enough distance, will separate and arrive at your ear at slightly different times.

river otter on ice
I wonder what this otter thinks of the singing ice?! Photo by David Lukas

This means that high-pitched sounds arrive first, followed almost immediately by lower-pitched sounds, creating a pinging, whiplash effect.

Depending on your point of view, these mesmerizing sounds are either ethereal and beautiful, or scary. For instance, there's nothing like the experience of walking out onto the middle of a frozen lake at night, then laying on the ice as it groans, shifts, and cracks loudly underneath you!

standing on ice
Walking across an ice-covered lake at night. Photo by David Lukas

I know that many of you don't live in places where lakes freeze in the winter, or where deep cold lingers into March. Today's newsletter is my way of sharing this unique experience with you. I hope you enjoyed this topic. 😄

A fun explanation of how these sounds are made.