Summary (tl;dr)

Idaho is experiencing an exceptionally rare late-June winter storm, bringing heavy snowfall to its mountain passes and a dramatic temperature drop, while simultaneously facing wildfire warnings in lower elevations.

Essential Background

Late June in Idaho typically marks the beginning of summer, with warm to hot temperatures often reaching the 80s and 90s in the valleys, increasing the risk of wildfires in dry areas. Such low-pressure systems bringing heavy summer snow to this part of Idaho occur infrequently, with the last notable event being in 2024.

The Full Story

A powerful cold front originating from the Gulf of Alaska has brought an abrupt and unseasonable shift in weather to the Northern Rockies. This system has caused temperatures to plummet by as much as 30 degrees, with valley highs dropping from the 80s and 90s earlier in the week to the 50s and 60s. Winter Storm Warnings and Watches are in effect for Idaho's mountain zones above 6,500 feet, with forecasts predicting 4 to 12 inches of heavy, wet snow, and localized totals potentially reaching up to 16 inches in some areas. This unusual snowfall coincides with Red Flag Warnings for wildfire danger in central and southern Idaho's lower elevations, presenting a dual and contrasting weather threat across the state.

Why It Matters

This unprecedented late-June winter storm poses significant risks for both residents and visitors during what is typically the peak summer travel and recreation season. Concerns include hazardous driving conditions on mountain passes, an elevated risk of hypothermia for unprepared individuals in the backcountry, and the potential for falling trees due to heavy, wet snow. The simultaneous alerts for winter weather in high elevations and wildfire danger in lower regions underscore the volatile and rapidly changing climatic patterns impacting the Western United States.

Geographic Location

• Bitterroot Range, along the Idaho and Montana border, United States (up to 8 inches of snow expected)
• Sapphire Range, along the Idaho and Montana border, United States (up to 8 inches of snow expected)
• Lemhi County, Idaho, United States (Winter Storm Warning, up to 12 inches of snow on highest peaks, including Lemhi Pass, Lost Trail Pass, Highway 28)
• Valley County, Idaho, United States (snowfall in higher-elevation areas)
• Stanley area, Custer County, Idaho, United States (snow dropping below 7,000 feet, several inches of snow expected near Galena Pass)
• Boise, Ada County, Idaho, United States (30-degree temperature drop, rain showers and thunderstorms)
• Central and Southern Idaho, United States (Red Flag Warning for wildfire danger)
• Bogus Basin, Ada County, Idaho, United States (snow possible above 7,500 feet, trace to 2 inches)