After record breaking highs earlier in the week, a sudden blast of heavy, wet snow caught some residents off guard.
The storm brought over 20 cm of snow, causing numerous car crashes and widespread power outages.
At the height of the storm, more than 80,000 people were left in the dark. Officials say most of the outages were due to snapped tree limbs falling down on power lines.
There were no significant delays reported at Denver International Airport as snow removal crews worked through the night to clear runways and de-ice planes.
Despite the problems the sudden change in weather caused, long-time residents embraced the first major snowfall of the season.
“You've got golf on Monday with friends, sledding with your grandkids on Wednesday and tee time already set again for Friday,” said one Colorado resident.
Another person admitted they weren't at all surprised by the early snowfall.
“I think you can always expect a snow around Halloween.”
The same system brought snow to Utah and Wyoming, where part of an Interstate Highway was temporarily shut down.