Ice Recording

Carmen Braden, on Prosperous Lake, May 2009. Ice thickness: 3 feet. Photo by Anthony Savidge

Note: All photos are by Carmen Braden except where indicated.

Equipment used for recording ice.

Gear necessary for ice recording: hydrophone, recorder, axe, ice auger, headphones, milk crate, backpack, notebook and pencil, tea, ice scoop.

4CracksBoom (track below) is from Wool Bay, Great Slave Lake, NWT. Recorder: Zoom H4). Hydrophone: Aquarian H2a. Ice depth: 3.5 feet. Water depth: 50feet approx. Temp: -30C, wind chill -35C. I spliced 4 sounds together, increased the gain by 20dB and applied mild noise reduction since the H4 is quite noisy in quiet moments when phantom power is being applied.

Close-up of equipment used recording ice

Hydrophone, recorder and ice scoop beside ice hole.

2CracksTHUD (track below). Same specs and processing as 4CracksBoom.  Beware – the THUD may be loud! If you listen closely you can hear a digital fuzzy noise every few seconds. Very annoying; perhaps it was caused the phantom power again.

Carmen holds an ice auger

The ice auger. Special thanks to Andrew Robinson for the loan of this one for the 2010 spring season. Photo by Bill Braden.

Carmen attempts to auger by herself.

Drilling through 3 feet of ice by hand alone is very difficult. Luckily, my on-site photographer lent a willing hand. Great Slave Lake, near Mocher Island. Photo by Bill Braden.

The sound of drilling an ice hole. The hydrophone is in another ice hole approximately 20 feet away at a depth of 10 feet. At first the drilling is smooth, but one point the auger bites into the ice and sticks, and I have to scrape to get going again.

Stickmen drilling an ice hole.

Method 1 for drilling through ice with a hand-auger.

Stick men drilling another ice hole.

Method 1a – when the drillers are smaller in stature.

Stickmen drilling yet another ice hole.

Method 2 is useful when the auger is partway through the ice.

Stickmen have almost drilled through the ice.

My preferred method of drilling though ice with a hand auger

Carmen holds her first hydrophone

My first hydrophone: the Aquarian (the silver and black end is the hydrophone). Photo by Bill Braden.

Carmen listens to the ice cracking.

While it appears I am warming my hands on the Zoom H4 recorder, in fact I am just amazed at the sounds I hear. Photo by Bill Braden.

The track below is full of Great Thumps.

My first experience listening to the ice cracking was in Wool Bay on Great Slave Lake. I’m not sure whether it was the -30 temperature, or whether the area was “unstable”, but there was a great deal of activity. Listening to the three tracks below should be with caution – many sounds are very quiet, but some are quite loud and there is no real warning when the loud ones occur. Be careful if you have your speaker or headphones turned up too loud!  The big cracks and booms often caused me to think that the ice was going to open up below and swallow me whole; not very likely given the general depth of the lake ice (3 feet). But there is a danger of being on a soft piece of ice where a current may be passing under – people have broken through when moving over these areas of rotten ice when driving, snowmobiling or even walking.

Wool Bay 1

Wool Bay 2

Wool Bay 3

Axe holding hydrophone cable.

Immobilizing the hydrophone cable by wrapping it around an axe handle, otherwise the weight of the hydrophone would drag it down. This is a method of depth control.

Carmen records ice on Propserous Lake.

Prosperous Lake, May 2010. Photo by Bill Braden.

The ice is thick enough by January to drive large trucks on. The ice is not as solid as it seems, and is made of many chunks of ice that are frozen together. This patchwork effect makes the ice bend and move like a wave when heavy vehicles move over it. The ‘wave’ will have a crest that runs in front of the vehicle, and if the vehicle drives too fast, it catches up with the wave and can break through the ice at this pressure point.

I found that the ice did make one or several large cracks before vehicles passed me. Once they had passed, the cracking was quieter and soon disappeared as the ice settled. In the track below, my sister drives our Ford Ranger on the ice road past the ice hole several times. The hole is approximately 500 meters from the ice road. I could not hear the engine at all, and only the tires making contact with the snow made any sound.

Jumping on ice on Prosperous Lake

Jumping to break the ice beside the dock. Ice thickness 1 foot. Photo by Bill Braden.

Landing on Ice

Landing on ice – trying to break through while recording. Photo by Bill Braden.

In the track below, I walk slowly towards a thin piece of ice and it creaks and bends with my weight until my foot breaks through. I pull it out, and do it again.

Carmen falls through the ice

Successfully breaking through the ice on Prosperous Lake. Photo by Bill Braden.

In the track below I break through again, and this time I thrash about for a minute simulating the sounds of an actual fall through the ice.

Sunset reflecting on ice.

Recording on Prosperous Lake, May 2010. Photo by Bill Braden.

In the track below, I am recording my Jez Riley French hydrophone in the left channel, and the Aquarian in the right channel. The French one is much more sensitive. I left the hydrophones approx. 200m. from shore and went back to the cabin and had some tea. There was no one else on the ice during the recording, so all sounds below are just the ice. It was early in the morning, and I think the change in temperature as the air heated caused the activity.

There is a strange sound, almost like a whale call near the end of this track.

The track below has some great cracklings and splinterings. The sounds have been likened to a dry wooden board being twisted and splintered.

The track below has some excellent long splinterings, almost like something is being dragged across the surface.

The track below has two CRACKS that sound very close. It is hard to get a sense of direction underwater, but it is easy to have a sense of distance when listening to the different cracks.

The track below has a higher frequency schluffing. The varieties in the sounds were amazing!

Here are some notes from the above recording I made during my initial listen:
– Sounds like a whale – zipps and groans for a second
– Like a gunshot
– Like a faraway cannon
– Higher frequency schuuuufsplinter
– Craaaaaaack
– Low thud somewhere
– Long splinter

Observe how the crack runs straight along the cleared area. The absence of insulating snow causes the ice to become thicker here, thus becoming more buoyant at this place. As it floats higher than the ice on either side, the pressure causes the ice to crack along the cleared area. Prosperous Lake, May 2009. Photo by Anthony Savidge.

The main obstacles for getting clean recordings of ice cracking are people, dogs and snowmobiles. The track below is a dog approaching from an island about 500 meters away. The sound of any movement on the snow surface is instantly transmitted and amplified through the ice. Even shifting one’s weight while standing will cause a ubiquitous and mainly unwanted scrunching noise.

Filming ice on Prosperous Lake, May 2009. Photo by Anthony Savidge.

Ice rotting in Prosperous Lake, June 2009

Filming candle ice in a canoe