# Did Mt. Saint Helen's Shatter Windows?

**URL:** <https://boards.straightdope.com/t/did-mt-saint-helens-shatter-windows/772401>\
**Category:** Factual Questions\
**Created:** [November 19, 2016, 3:47am UTC](https://boards.straightdope.com/t/did-mt-saint-helens-shatter-windows/772401 "2016-11-19T03:47:57Z")\
**Posts on this page:** 2\
**Page:** 2

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**Author:** ![racer72](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/racer72/32/3075_2.png) [@racer72](https://boards.straightdope.com/u/racer72)\
**Post date:** [November 20, 2016, 10:47pm UTC](https://boards.straightdope.com/t/did-mt-saint-helens-shatter-windows/772401/21 "2016-11-20T22:47:59Z")

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I was in Yakima when the mountain blew. We heard a “whump” sound then about 5 seconds of rumbling. A radio station announced about 5 minutes later what happened. I bailed out of town to get home to Tacoma. Glad I did, those that stayed had to deal with ash about an hour later.

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**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\
**Post date:** [November 21, 2016, 3:58am UTC](https://boards.straightdope.com/t/did-mt-saint-helens-shatter-windows/772401/22 "2016-11-21T03:58:48Z")

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> [@susan](#):
>
> \*\*Yet many areas closer to the eruption (Portland, Oregon, for example) did not hear the blast. \*\*This so-called “quiet zone” extended radially a few tens of miles from the volcano and was created by the complex response of the eruption’s sound waves to differences in temperature and air motion of the atmospheric layers and, to a lesser extent, local topography.[5]" [emphasis added].

The phenomenon of Acoustic Shadows were first encountered during The American Civil War; sounds of battle could often be head in far away locales when an audience markedly closer to the battlefield heard nothing.

> **[Acoustic shadow](https://en.wikipedia.org/wiki/Acoustic_shadow)**
>
> An acoustic shadow or sound shadow is an area through which sound waves fail to propagate, due to topographical obstructions or disruption of the waves via phenomena such as wind currents, buildings, or sound barriers.
> A short-distance acoustic shadow occurs behind a building or a sound barrier. The sound from a source is shielded by the obstruction. Due to diffraction around the object, it will not be completely silent in the sound shadow. The amplitude of the sound can be reduced considerably,...

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