Thanks, I see that Lahars are technically associated with volcanoes as another comment noted. They have a variety of causes of which glacial collapse is one. [0] The term jökulhlaup describes a flood originating from a glacier, for example draining of a glacial lake. [1] It now seems the Nepali flood was triggered by a landslide onto a glacier.

As a practical matter the effects are pretty similar. Rainier has had lahars and jökulhlaups in the past.

[0] https://en.wikipedia.org/wiki/Lahar

[1] https://en.wikipedia.org/wiki/J%C3%B6kulhlaup