giant snowball may have killed mammoths!

[G-spotter]

death from above

[EWolfe]

wZr8jXo1Uso

[archenemy]

Figures it hit Canada.

[tvashtarkatena]

I'm guessing this phenomenon is where the phrase

"You don't have a snowball's chance in Hell" comes from.

[catbirdseat]

As for the crater created by the impact, the scientists say it would have formed on the kilometres-thick ice that covered Canada at the time and melted away with the ice

I suppose it's possible. A metallic or stony meteoroid would have punched through an ice sheet, even if it were kilometers deep, but a comet might not have.