Angel Glacier is a glacier in Jasper National Park. As noted in the wikipedia article, like so many Canadian glaciers it was much larger once, but has been melting furiously under the onslaught of global warming. According to this fellow on twitter, a large chunk of it might just have collapsed:
There appears to have been some damage to the park facilities:
The glacier is so-named because it seems to consist of a pair of swept out wings. What seems to have happened (if this account is accurate) is a chunk of one of them fell into a nearby lake and kicked up a wave big enough wash over an activity area. And this kind of thing is not unheard of. The largest tsunami ever recorded occurred at Lituya Bay, Alaska in 1958 when an earthquake dropped a huge chunk of rock into the water.