Summer snow in Montana, NWS issues rare June Winter Storm Watch

An unexpected cold front is bringing a wintry mix to Montana just as summer approaches. With a Winter Storm Watch in effect, heavy snow is expected in the high elevations of the Rockies, disrupting travel and creating hazardous conditions.

• Late-season wet snow is forecast for the northern Rockies on Monday and Tuesday, June 17 and 18, 2024.
• Temperatures will be well below normal for mid-June and even near record cold for the date.
• Heavy wet snow may cause tree damage and power outages, and will likely make travel difficult across some of the passes.
• This event marks only the sixth June since 2005 to have a Winter Storm Watch in Montana.

As the summer solstice approaches, some regions in the high-elevation West are experiencing unusual wintry conditions, including threats of accumulating snow. This unexpected weather pattern is due to a cold upper-level low that moved into the Pacific Northwest over the weekend and is now progressing into the Intermountain West as the workweek begins.

By Monday and Tuesday, June 16 and 17, the upper-level low is expected to settle into western Montana and central Idaho, bringing the potential for heavy snow along the northern Rockies.

Winter Storm Watches have been issued for large areas of the Montana and Idaho mountains. Forecasts predict 5 – 10 cm (2 – 4 inches) of snow for Lost Trail Pass, 10 – 20 cm (4 – 8 inches) above 1 829 m (6 000 feet) in Glacier National Park, and 15 – 30 cm (6 – 12 inches) in the Sapphire and Bitterroot ranges.

This event marks only the sixth June since 2005 to have a Winter Storm Watch in Montana, according to Iowa State University’s Iowa Environmental Mesonet.

National Weather Service (NWS) meteorologists in Great Falls, Montana, issued a Winter Storm Watch early Friday morning, June 14, warning of heavy, wet snow expected to begin on Monday morning and last until Tuesday evening, June 18. The watch covers higher elevations, particularly in the Continental Divide along the Rocky Mountain Front, where up to 30 cm (12 inches) of snow is anticipated.

During this period, temperatures in Great Falls are forecasted to fall to lows of 4 °C (40 °F), with highs barely reaching 10 °C (50 °F). These cool temperatures could contribute to significant mountain snow at higher elevations.

The NWS advisory cautions that travel could be difficult, especially on backcountry roads, and recommends that those in the backcountry ensure they have the appropriate knowledge and gear. The wet nature of the snow can bring down tree limbs and power lines, posing additional hazards.

Despite the current cold snap, long-range forecasts indicate that this “summer” chill will not last. Temperatures are expected to return to seasonal averages by the end of the week, with the potential for hot weather looming after next weekend.

References:

¹ Short Range Public Discussion – NWS – June 16, 2024

² Snow in mid-June? Winter Storm Watches posted in West as summer takes a break- Fox Weather – June 16, 2024

³ Montana to receive ONE FOOT OF SNOW on Monday June 17th, June 16, 2024 – CWR – June 16, 2024

Featured image credit: NOAA, Zoom Earth, The Watchers. Acquired at 23:40 UTC on June 16, 2024