Predil Lake Notebook (and a Frozen Alpine Lake Ice Composition)

We made a brief stop at the Lago del Predil in northeast Italy on Sunday (21 December), long enough to make a short video featuring our fledgling talents for acoustic dispersion composition and to collect a few notes for the next time we’re passing through this picturesque alpine valley in eastern Italy.

Acoustic Dispersion

First, the composition.

As soon as we stepped out of our car we began to hear these laser-like chirps echoing through the valley, the eerie sounds bouncing off of trees and the lake’s frozen surface. I thought it was a bird (of course). It was sound bouncing off of the lake’s ice, but its origins weren’t from a winged creature. It was created by rocks skipping and skimming over the frozen lake, where the sounds react differently depending on the thickness of the ice. At first I was irritated. But I was quickly sucked in. An explanation from How Stuff Works:

Sound waves are made up of multiple frequencies, including high ones and low ones. When a sound travels through air, its component frequencies usually travel together at the same rate, so they all reach the human ear more or less simultaneously.

But sometimes, when a sound wave passes through a solid medium (like ice), those high and low frequencies get separated. Being faster, the high-frequency wavelengths zip ahead of their low-frequency counterparts. As a result, you may hear a gap between the high notes and the low notes contained within the same sound. That’s acoustic dispersion in a nutshell.

The 30-second video we created, cleverly entitled ‘The Singing Ice of Lago del Predil’, is below. Sound on!

Here’s a BlueSky post of the video. If you hang out there, please give it a like or share it. (Thank you!)

The singing ice (aka acoustic disperion) of Lago del Predil, a lake on the Slovenian-Italian border in the Julian Alps. (Volume on!)With a surface area of about 1sq km, it's the second largest natural lake in Italy's Friuli-Venezia Giulia region.21 Dec 2025#JulianAlps #NaturePhotography

— Bob Ramsak (@bobramsak.bsky.social) 2025-12-22T11:46:09.534Z

Predil Lake

With a surface area of about 1 square kilometre, Lake Predil is the second biggest natural lake in Italy’s Friuli-Venezia Giulia region. It sits in a high valley (969m/3179ft) just north of the Sella Nevea pass and Ski resort, and just a few kilometres from the Slovenian border via the Predil Pass road.

It sits in a beautiful setting with towering peaks of the Julian Alps on all sides, making it a popular stop or destination in the summer months for day-trippers and hikers. I experienced those crowds during a few drives through the area during the summer, but we encountered few people on Sunday afternoon. I suspect that’s due mostly to the lack of snow and subsequent slow start to the ski season, keeping most early winter visitors away.

To get your bearings, here’s a map.

For future reference:

• 5.8km Giro del Lago del Predil loop trail (AllTrails)
• A good write-up and history of the lake on the Erjavceva Hut website
• Another nice write-up from the Explore Friuli-Venezia Giulia blog

A few more images below, all taken on Sunday 21 December 2025.