Further to the debate on the lyrics in the third verse, it is "roarin' like the flood at Yule".

Yule is a period of time, which includes the Christmas period, and, being deep in mid-winter, is prone to heavy snow and sleet which, upon thawing, would produce flooding in streams and rivers.

Further, the sixth line of verse three is "Birlin' by the Garry's pool".

Thus, with one or two amendments, the third verse is:-

Like a torrent doon the mountain
Swept the avalanche o’ steel
Rose the wild cry o’er MacDonald
Flashed the claymore o’er Loch Eil
By the red leaves o’ the summer
Burlin’ by the Garry’s pool
Came the whirlwind o’er the heather
Roarin’ like the flood at Yule