Environment Canada ended its tornado warnings for Wetaskiwin County, Leduc County and Brazeau County just before 6:30 p.m. Thursday.
Severe thunderstorm warnings also ended for much of the northern half of the province as multiple storm systems brought hail, heavy rains and high winds throughout the evening.
This video was taken about eight kilometres northwest of Breton:
The Drayton Valley storm's rotation appeared to slow down around 6 p.m., according to Nevin deMilliano with Prairie Storm Chasers.
He watched the storm unfold just east of Drayton Valley.
"This is the biggest storm that I've ever seen in Alberta," said diMilliano, who has a decade of experience chasing severe weather in the province.
"It's the most unreal thing that I've ever seen ... you can't even describe it, it's that crazy."
Pictures and videos posted to diMilliano's Twitter account show a churning mass of dark clouds.
"It's huge," he said. "It's like it's alive."