You are thinking of Lake Bonneville, the ancestor of the Great Salt Lake, formed about 30,000 BC from glacial runoff, drained into the Columbia River through Idaho around 124,000, probably due to continued glacial melting.
No, he is thinking of Glacial Lake Missoula. That’s the one that drained rapidly (and sequentially), forming the channeled scablands of Washington State.
Lake Bonneville disappeared mostly due to evaporation (hence the salt deposits at Great Salt Lake).