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FelisCantabrigiensis t1_j6f9lmn wrote

100% truth.

Cannon firing explosive shells, or hand-held explosives, are used to trigger avalanches deliberately to reduce risk to people moving in mountainous areas with heavy snow.

You didn't ask how loud a noise. The answer is "very loud" - explosions. Yelling loudly won't do it.

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djublonskopf t1_j6hm4xn wrote

A snow-slab avalanche is triggered by structural failure in a weak layer of snow beneath the "slab". It takes 200-500 Pascals of pressure change to cause the weak layer to structurally fail and trigger an avalanche—easy enough for explosives or a skier directly atop the snow.

The sound wave of a loud human scream can only achieve a pressure amplitude of about 2 Pa, however, which is two orders of magnitude too weak. Even a passing jet plane would only see a wave amplitude of 20 Pa, although the shockwave of a passing supersonic jet can be enough (the study that proved this, while I don't have a link, was amusingly titled Opération "Bangavalanches".)

So, no, somebody yelling loudly is not going to trigger an avalanche, but a passing supersonic jet shockwave might.

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TheLostHippos t1_j6i675i wrote

Replying to saywherefore (#1,597,509)

At a far enough distance it does behave exactly the same as acoustic waves.

"In particular, shock waves travel faster than sound, and their speed increases as the amplitude is raised; but the intensity of a shock wave also decreases faster than does that of a sound wave, because some of the energy of the shock wave is expended to heat the medium in which it travels. The amplitude of a strong shock wave, as created in air by an explosion, decreases almost as the inverse square of the distance until the wave has become so weak that it obeys the laws of acoustic waves."

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