What does wilderness sound like?

At over 13,000 square miles, Gates of the Arctic National Park and Preserve in Alaska is the second largest national park in the United States, after Wrangell-St. Elias National Park and Preserve. Gates of the Arctic does not contain a single road, so most visitors access the park by bush plane. Here, Brooks Range Aviation pilot Garrett Heusser flies through the Brooks Range on the way to audio recording sites.

Some of the many lakes in the Alatna River Valley from the air. In the right rear of the photo is a classic oxbow lake, formed when a bend in the river was cut off from the main channel.

There are no suitable landing areas within the Arrigetch Peaks, so trips are multi-day ventures that involve hauling the audio recording equipment by hand. Heusser drops the researchers off at Circle Lake, an oxbow lake in the Alatna Valley, one of several landing areas used to access the Arrigetch.

Dan Walsh and Davyd Betchkal, of the Natural Sounds and Night Skies Division in the Park Service’s wilderness program in Alaska, set up the recording station at Lake Omelaktavik after a rain squall passed.

Rain clouds retreat into the distance in the Noatak River Valley.

The aircraft, a 1957 de Havilland Beaver, waits on Lake Omelaktavik while Walsh and Betchkal set up the sound station. The model was no longer produced after 1967, making the newest Beavers over 50 years old. In spite of their age, Beavers are still a coveted bush plane and one of the primary workhorses of rural Alaska.

“Arrigetch,” in Iñupiat, means “fingers of the hand outstretched.” The summits, right to left, are Caliban, Ariel and Xanadu.

The recording station includes basic instruments to record weather data to give context to the sound files. Wind, for example, interferes with the audio recordings by pushing around the microphone and producing “pseudo noise.” Measuring the wind speed helps the researchers correct for distortion.

Betchkal and Walsh pose with their completed sound station in Arrigetch Creek. Wind direction data are also useful for understanding the recordings, as a breeze can “push” noise in one direction or another — for instance, if a babbling creek is upwind, it may be more easily audible than on a calm day.

The Arrigetch Valley has one major fork, where the Aquarius Valley splits off to the south. Water draining from the Aquarius Valley boosts upper Arrigetch Creek, particularly after the afternoon heat causes snowmelt.

Spring arrived late this year across Alaska, and in June ice and snow were still abundant in shady areas.

An unnamed lake in the north fork of the Aquarius Valley. Heusser, the bush pilot, thought he could land on this lake, but added that, “if I’m wrong, I’d have some explaining to do.”