They require the Storm phase to be active. There's probably a way to detect this, but I haven't looked into it.

See https://www.wowhead.com/news/how-to-obtain-thrayir-eyes-of-the-siren-in-patch-11-0-7-stormcrow-mount-354470

Import string:

AV4xXlReU2l0ZW1zXlReTjQwXlReU2VuYWJsZWReQl5TdHlwZV5TSVRFTV5TbWV0aG9kXlNaT05FXlNyZXBlYXRhYmxlXkJeU2RhdGVzXlReTjIwMjQxMjE4XlReU2F0dGVtcHRzXk4xXnRedF5TYXR0ZW1wdHNeTjFeU25hbWVeU1RvcnJlbnRpYWx+YEZyYWdtZW50XlN6b25lc15UXk4xXlMyMzY5XnReU2NoYW5jZV5OMTAwXlNleHBvcnReQl5Tc2Vzc2lvbl5UXlNhdHRlbXB0c15OMV50XlNpdGVtSWReTjIzNDMyOF50XnReU3NpZ25hdHVyZV5TUkZJMlBENGpPakowTm50Z0luYy9aQT09XlNidWlsZF5ONzM4XnReXg==

Source: https://www.wowhead.com/item=234328/torrential-fragment