The 400-metre-wide slide of snow and debris came down at about 9:30 in the morning.
Initially, RCMP said they weren't sure if any vehicles were under the heavy, packed snow.
Greg Bruce, district operations manager with the Transportation Ministry, said they have confirmed that no vehicles were caught by the slide and no one was injured.
However, RCMP said that a person in a pickup truck did attempt to get through the slide and became stuck in the debris and packed snow.
No detours were available to get around the slide, but the highway was re-opened around 6 p.m. Monday.
Bruce said an avalanche technician was over at the slide assessing the potential danger Monday afternoon. Avalanche control was expected to begin immediately after the assessment.
"The area has received 50 to 60 centimetres of snow over the last three days," he said in an interview.
"Snowpack levels at our Robson weather station, which is really close to where the avalanche took place, is sitting at a higher level than we've seen it in the last 20 years at this time."
The heavy snow over the weekend was followed by a deluge of heavy rain Monday.
"Conditions deteriorated rapidly," Bruce said.
Flagger crews were at both ends of the slide, and in Tete Jaune, McBride, Valemount and Jasper, Alta.
Highway 1 and Highway 23 were also closed due to avalanche danger.
Canadian Avalanche Centre forecaster Eirik Sharp said the most dangerous areas are currently parts of the Sea-to-Sky highway on B.C.'s south coast, and the Columbia Mountain region in the Interior.
While the danger of natural avalanches has subsided since the weekend, backcountry enthusiasts should be wary of the heightened threat of human-triggered slides, Sharp said from Revelstoke.
"People are going to be chomping at the bit," he said. "Riding conditions across the province haven't been very good until this point and on the surface now with this good load of snow, things are looking really good."
However, weak layers of snow from a snowfall in early December have created a hidden danger for people enticed by fresh snow, Sharp said.
"Until we get more evidence that those layers are settling out and being less of a problem, conservative decision-making is definitely going to be the best strategy for staying safe in the backcountry, and avoiding large open terrain," he said.
"It's kind of like crossing a mine field right now. On a slope there are weak points where your likelihood to trigger an avalanche is increased.
"You could be lucky and you could run through the mine field and not touch one of them, but if you were to step on one of those mines, the consequences are going to be significant." (CHNL, The Canadian Press)
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