A surface low tracked across southern Idaho and brought periods of moderate to heavy snow to Idaho and Lemhi Counties.
Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS MSO wrote it up.
A surface low tracked across southern Idaho and brought periods of moderate to heavy snow to Idaho and Lemhi Counties.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Missoula, MT wrote its last area forecast discussion before the first event at Feb 6, 2:07 PM PST, 6 hours 28 minutes earlier.
Area Forecast Discussion
National Weather Service Missoula MT
307 PM MST Thu Feb 6 2025
.DISCUSSION...
KEY MESSAGES:
- A winter storm coming through tomorrow morning will mainly
affect areas south of Interstate-90.
- Several inches of heavy, wet snow may impact the lower
elevations of Idaho county, including Riggins.
- Blowing and drifting snow are a major concern for Ravalli
county, Montana, especially the southern portions of the county.
- Lemhi county, ID and southwest Montana including Butte will
receive a few inches of new snow in the valley and several in
the mountains from this next storm.
Another weather system is moving through the region tomorrow with
the most significant impacts expected south of Interstate-90. This
is a very wet system that will interact with the cold air already
in place over Montana, and some places in Idaho will pick up more
wet snow. Overall, the system will move pretty quickly with only
about 6-8 hours of significant impacts expected in any given area
before things start to calm down.
For southern central Idaho, another round of heavy, wet snow is
expected. Riggins Idaho reported 11 inches of snow with the last
storm, and another wet storm is on the way that will bring a
quarter to half an inch of moisture with. Uncertainty remains how
much snow that will translate too, and it's much less than the 1.7
inches of moisture they recently picked up, but it may still
exacerbate the problems with power outages and downed trees in
that area.
As the low pressure digs into Oregon and Idaho, it will cause
easterly winds in Montana to develop. This will pull more cold air
back into Ravalli County, Montana and cause what is called a deep
dendritic growth zone to develop. This means that there will be a
deep layer where snow crystals can grow rapidly, ultimately
resulting in very light, fluffy snow. Add to this a resurgence in
the north winds, and even if there's only a few inches of snow, it
will be blowing and drifting snow. While the amount of forecast
snow isn't really high in the terms of how much water it carries,
it will still be difficult to control and keep roadways clear.
Friday morning will be difficult in southern Ravalli County.
Lemhi County Idaho will also receive some snow and winds with this
storm. Due to some downslope flow, we expect less accumulation,
but once again, winds will play a major role in the impacts in the
valleys there as well. In the mountains along the Continental
Divide, just the opposite will happen as there is upslope flow and
several more inches of snow are possible there.
Elsewhere across the region a few inches of snow and some winds
will cause moderate impacts and some minor travel delays. Winter
weather advisories have been issued for these areas.
The weather pattern will remain active through next week. The
region will remain under northwest flow with shortwaves rolling
through every couple of days causing more light to moderate snow
showers. These will often bring a low density, fluffy snow that is
easy to remove but packs down and becomes slick very quickly. So
plan on an extended period with intermittent travel inconveniences
through the middle of the month.
&&
.AVIATION...Snow showers are causing intermittent obscurations
across the region, though they are expected to decrease this
evening. Tomorrow morning another storm system will move through
mostly south of I-90 mainly impacting terminals KHRF and KBTM,
though some minor impacts and VFR flight conditions can be
expected at other area terminals as well.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory from 3 AM to 4 PM MST Friday for Lower
Clark Fork Region.
Winter Storm Warning from 3 AM to 4 PM MST Friday for
Bitterroot/Sapphire Mountains...Missoula/Bitterroot Valleys.
Winter Weather Advisory from 3 AM to 5 PM MST Friday for
Butte/Blackfoot Region.
ID...Winter Weather Advisory from 3 AM MST /2 AM PST/ to 4 PM MST /3
PM PST/ Friday for Eastern Lemhi County...Northern
Clearwater Mountains...Orofino/Grangeville Region...
Southern Clearwater Mountains.
Winter Storm Warning from 3 AM MST /2 AM PST/ to 4 PM MST /3 PM
PST/ Friday for Lower Hells Canyon/Salmon River Region...
Western Lemhi County.
&&The national radar mosaic for the moment the first event began.
2 winter storm, 1 winter weather, 1 heavy snow. Local standard time, as filed.
The Grangeville COOP reported 4.8 inches of snowfall, while the airport recorded north winds between 10 and 13 mph. The webcams showed snow-covered roads.
Nine to ten inches of snow were reported on Williams Creek Summit. Given that high elevation stations like the Red Rock Peak RAWS recorded westerly winds of 15 to 31 mph, blowing and drifting snow were likely occurring at the summit.
The Lemhi County Roads Department described the storm as a 'high-end event'. They reported 3 inches of snow overnight in Salmon, followed by another 4 inches between 0600 and 1000, for a storm total of 7 inches. Snow falling on already icy roads made travel very difficult, prompting the declaration of emergency-travel-only status. They also reported a 30-minute period of intensified winds, resulting in near-zero visibility. Additionally, a road grader flipped on the ice, though the driver was not injured.
Idaho Transportation Department (ITD) reported 10 to 12 inches of snow at Whitebird Grade and 3 to 4 inches towards Riggins. ITD cameras showed heavy snow accumulating on U.S. Highway 95 between 0600 and 0730PST. Riggins also experienced tree damage and power outages that lasted 12 to 24 hours after the storm.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2025Every state in 2025This day in weather historyWarnings in Idaho, February 2025
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1239706, 1239725, 1237564, 1237556.