Colorado's high country faces another full day of winter driving on Monday, November 2, with a National Weather Service winter weather advisory in force from 5 a.m. until midnight MST for the mountains above 9,000 feet — a zone that includes the Eisenhower Tunnel on Interstate 70, Berthoud Pass on U.S. 40, Breckenridge and Winter Park. Forecasters expect 3 to 7 inches of new snow through the day in that zone, falling on both the Monday morning and Monday evening commutes, on the state's busiest east–west trucking corridor.

“Plan on slippery road conditions. The hazardous conditions will impact the Monday morning and evening commutes,” the National Weather Service said in the advisory, as reported by Men's Journal. The advisory covers the mountains of Summit County, the Mosquito Range and the Indian Peaks. The 9,000-foot line matters: the forecast does not promise the same accumulation in every town or valley below it, and conditions can change sharply between the start of a climb and a pass summit.

Why the snow is still falling after the storm moved on

The weekend storm that soaked the Southwest and flooded parts of Arizona and southwestern Colorado is moving east, but colder air wrapping in behind it is keeping snow going over the northern and central Colorado mountains. “A colder northwest flow on the backside of the storm will favor additional snowfall across Colorado and parts of Wyoming,” OpenSnow meteorologist Alan Smith explained. AccuWeather's Dan DePodwin, vice president of forecast operations, said snow levels, initially very high, “will work their way down to some intermediate elevations into early this week.” Denver7's forecasters, via Krystal 93, put Monday's snow level at about 8,000 to 8,500 feet, with mountain totals of 5 to 10 inches and the heaviest amounts across the northern mountains, and strong north winds developing across the plains.

Along I-70 itself, the National Weather Service point forecast for Frisco calls for snow showers through Monday with a 90 percent chance of precipitation and 1 to 3 inches of accumulation possible, with west-northwest winds of 14 to 16 mph gusting to 31 mph. Snow showers are likely to continue Monday night, mainly before 11 p.m., with gusts to 33 mph and temperatures falling to about 20 degrees — cold enough for anything that melted during the day to refreeze on the roadway overnight.

What it means for the I-70 corridor and for truckers

Interstate 70 west of Denver is Colorado's main mountain freight route, and its two high crossings — the Eisenhower–Johnson Memorial Tunnel, at about 11,000 feet, and Vail Pass — sit squarely inside the advisory's elevation band. Berthoud Pass, which carries U.S. 40 to Winter Park and the northwest of the state, is in the same zone. For the many Punjabi and other long-haul drivers who run I-70 between Denver, the mountain towns and Utah, Monday is a day to plan around the passes rather than through them: snow falling through both commute periods, gusty crosswinds on exposed stretches, and refreezing surfaces after dark.

The National Weather Service advises drivers to slow down and use caution, to check COtrip — the Colorado Department of Transportation's road-conditions service — for current restrictions, closures and chain requirements before heading toward a pass or the tunnel, and to clear a vehicle completely before setting off: “Make sure your vehicle is completely clear of ice or snow before starting the trip. Flying snow from cars causes accidents.” Under Colorado's winter rules, commercial vehicles travelling I-70 through the mountains must carry chains through the season, and the transportation department can impose traction and chain restrictions as conditions worsen; passenger vehicles on the corridor must meet the state's traction requirements. No full closure of I-70 had been announced in the forecasts reviewed for this report, but restrictions can change within an hour in weather like this.

The wider picture: a state split by elevation

Monday's Colorado weather is two stories written by altitude. The Front Range and the plains, including Denver, get a cooler, wetter day of scattered rain showers rather than snow, with a few flakes possibly mixing in around the Palmer Divide on Monday night. Far south, a separate set of winter storm warnings has covered the San Juan Mountains of southwestern Colorado, where the same storm system brought flooding along the San Juan River near Pagosa Springs and much heavier snow above 10,000 feet. The northern advisory zone is the tail of that system, not a new storm — but for drivers it is a full day of winter conditions in its own right.

What happens next

The advisory ends at midnight MST on Monday night. Tuesday is forecast to be mostly dry across the state, with partly cloudy skies in the advisory zone, highs of 34 to 44 degrees and gusts up to 35 mph — a clearing day, though not a guarantee that every pass road will be clear by morning. Another weak system could bring a few showers and light mountain snow on Wednesday, according to Denver7's outlook, before the rest of the week turns mostly dry with temperatures near seasonal averages. Snow levels are expected to keep falling as colder air settles in, so later systems this week would need less elevation to produce snow on the roads.