Video of Peru glacier collapse (mostly aftermath)

Huffington Post has an article about the collapse of the glacier in Peru, which triggered an inland tsunami:

Huge glacier breaks apart in Peru, triggering Andes tsunami

So basically this big block of glacial ice broke off, and slid into nearby lake.

Quick quote: ""This slide into the lake generated a tsunami wave, which breached the lake's levees, which are 23 metres high -- meaning the wave was 23 metres high," said Patricio Vaderrama, an expert on glaciers at Peru's Institute of Mine Engineers.

In my book, that's a pretty big wave in a lake.