Winter storm warnings and advisories in effect across the northern Rockies and Intermountain West, USA

Multiple winter storm warnings and winter weather advisories are in effect across Idaho, Montana, Washington, and Colorado. The warnings and advisories, issued overnight into Friday morning, December 5, forecast mountain snow, gusty winds, and low visibility to last into Saturday.

Areas under winter storm warnings include the Central Idaho Panhandle Mountains, where Lookout Pass, Kellogg, and Wallace will remain under warning through 16:00 PST Saturday. In Montana, warnings will be in effect across the Little Belt, Big Belt, Bridger, and Gallatin Mountains through 14:00 MST Saturday.

Eastern Idaho’s Teton Valley, Bear River Range, and Caribou Range are also under warnings, with several Pocatello zones scheduled to expire earlier around 05:00 MST Saturday. In Colorado, the Sawatch, Mosquito, Gore, Elk, and Flat Tops ranges are under warnings through late Saturday or early Sunday.

Winter weather advisories extend into adjacent and lower-elevation regions. Western Chelan County in Washington, including Stehekin and Stevens Pass, is expecting 13–25 cm (5–10 inches) of snow with gusts up to 55 km/h (35 mph). In Montana, the Elkhorn and Boulder Mountains and the Gallatin Valley remain under advisories through Friday morning for minor additional accumulations up to 2.5 cm (1 inch).

Advisories in Northeast Montana, are in effect from Valley County to Richland and Dawson Counties, with 5–10 cm (2–4 inches) of snow being forecast from Friday night through midday Saturday.

Eastern Idaho’s Upper Snake River Plain, Sawtooth/Stanley Basin, and Sun Valley Region are also under advisories, with 5–15 cm (2–6 inches) of snow and stronger winds being forecast to develop late Friday. The Rabbit Ears Pass region in Colorado remains under an advisory through Friday evening before transitioning to a storm warning later that night.

Snowfall totals of 15–30 cm (6–12 inches) are forecast for mountainous parts of Idaho Panhandle above 900 m (3 000 feet), 25–46 cm (10–18 inches) for eastern Idaho and Montana ranges, and 30–61 cm (12–24 inches) for Colorado and Montana high terrain. Winds on exposed ridges are forecast to gust between 70 and 90 km/h (45–55 mph), occasionally reaching 100 km/h (60 mph).

Valley and advisory areas are expected to receive 2–8 cm (1–3 inches) of snow, locally higher near passes, with brief rain or snow transitions Friday afternoon. In the Idaho Panhandle, Lookout Pass may switch to rain briefly before colder air returns and snow resumes.⁵

Travel conditions will range from difficult to impossible in the higher mountain zones, and occasionally hazardous in advisory areas.

Tire chains may be required on several passes, including Kings Hill Pass in Montana and Vail Pass in Colorado. Blowing snow is expected to reduce visibility, while wet, heavy snow and strong winds could down branches or cause localized power disruptions. Backcountry travel faces deep snow and an elevated avalanche risk.

References:

¹ Winter Storm Warning – NWS – December 5, 2025

² Winter Weather Advisory – NWS – December 5, 2025

Rishav Kothari

I am an Assistant Editor and Severe Weather & Science Journalist at The Watchers, specializing in real-time severe weather coverage, geophysical event reporting, and research-driven scientific analysis. You can reach me at rishav(at)watchers(.)news.

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