The site's demo is broken because of origin security.
https://soledadpenades.com/articles/three-js-tutorials/rendering-snow-with-shaders/
Error: Mixed Content: The page at 'https://soledadpenades.com/articles/three-js-tutorials/rendering-snow-with-shaders/' was loaded over HTTPS, but requested an insecure resource 'http://soledadpenades.com/files/tutorials/three.js/snow_with_shaders/step10.html'. This request has been blocked; the content must be served over HTTPS.
Clicking the link, the demo is fine when loaded by itself, this might not be the only demo with the issue.