Ice Climbing On Frozen Waterfalls

Finally, Canadian Rockies WI grading does NOT have anything to do with whether a climb is multi-pitch or not. Therefore, a 4-pitch WI5 is not granted WI6 just because it's long, and likewise a 4-pitch WI6 is not given WI7.
WI2 - low-angled (60 degree consistent ice), with good technique can be easily climbed with one ice axe. Grades beyond this generally require the use of two ice tools.
WI3 - generally sustained in the 60-70 degree range with occasional near-vertical steps up to 4 metres (Cascade Waterfall, Banff; This House of Sky, Ghost River)
WI4 - near-vertical steps of up to 10 metres, generally sustained climbing requiring placing protection screws from strenuous stances (Professor's Falls, Banff; Weeping Wall Left, Icefields Parkway, Banff; Silk Tassle, Yoho; Moonlight & Snowline, Kananskis)