Answer:
arctic stream with warm air from gulf of Mexico
Step-by-step explanation:
In my opinion and based on recent forecasts I have seen, it´s is due to the very cold stream that came from the arctic pole(upper-level winds) in additions with some warm clouds came from the south. I think that due to the fact that Denver is located to the East of the Rockies (Colorado), near east Denver should be protected by the high mountains and the very far east cities might be more vulnerable to very high snowfall.