Saturated soils caused by abundant rainfall during early February lead to a fallen tree and traffic accident on US Highway 12.
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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.
Saturated soils caused by abundant rainfall during early February lead to a fallen tree and traffic accident on US Highway 12.
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 5, 2:12 AM PST, 1 hour 48 minutes earlier.
Area Forecast Discussion
National Weather Service Missoula MT
312 AM MST Mon Feb 5 2018
.DISCUSSION...A Tale of Two Airmasses exists yet again today, with
arctic air infiltrating extreme northwest Montana and down around
the McDonald Pass/Ovando/Lincoln region of west central Montana.
Snow mixing with freezing rain will continue today, causing
difficult travel conditions through the day. Mountain passes
crossing the Continental Divide will see periodically reduced
visibility in addition to slick road surfaces, due to snow and
blowing snow.
West of these locations, a much milder airmass continues to
dominate. Temperatures have stayed in the 30s and 40s overnight,
with little diurnal trend expected today. High snow levels will
stay up around the 5000 to 6000 feet range across much of central
Idaho and west central Montana through the day as well. One to
two inches of rainfall is still expected across Clearwater and
Idaho counties in Idaho. Loose soil, rock falls, and debris over
roadways as a result of runoff and melting snow should be
anticipated in these locations over the next 24 hours. In
addition, small stream rises are occurring and will continue to
rise through the course of the next one to two days. In addition
to hydro concerns, avalanche danger will be on the increase today
across central ID and west central MT as well.
Tuesday will see diminishing precipitation overall with cooling
temperatures and lowering snow levels. That being said, mountain
snow will continue along the Divide and along the ID/MT border
Tuesday into Wednesday with minor accumulations expected.
Northwest flow will continue to support terrain based showers on
Wednesday afternoon into Thursday with accumulating snow above
5000 feet, especially across Northwest Montana. Mountain top winds
will be strong enough to result in downsloping and relatively dry
conditions for many valleys on Wednesday, but by Thursday valleys
will stand a better chance of seeing rain showers.
Forecast models continue to trend toward a deeper trough by
Friday, leading to another dramatic change in the weather.
Consistency amongst the models has been lacking in recent days
thus confidence is only moderate in another Arctic cold front
marching across the region. But there is a growing potential for a
period of strong winds, blowing snow, a period of heavy snow and
icy conditions Friday into Saturday. Please stay tuned as details
become more evident over the coming days.
&&
.AVIATION...Widespread precipitation will impact all terminals
through the day today. KGPI will be the only terminal which will
be impacted by snow. Expect rain at KMSO, KBTM and KSMN, although
KBTM may see a brief mix of rain and snow around 05/1500Z or so.
All terminals can expect frequent lowering of ceilings and
visibility through 05/2300z. In addition, gusty northeast winds
may impact KGPI between 05/1200z and 05/1800z. Precipitation and
winds will diminish wholesale across the region after 06/0000Z.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory until 8 AM MST this morning
Flathead/Mission Valleys.
Winter Storm Warning until 8 AM MST this morning West Glacier
Region.
Winter Weather Advisory until 8 AM MST this morning
Potomac/Seeley Lake Region.
ID...None.
&&The national radar mosaic for the moment the first event began.
1 heavy rain. Local standard time, as filed.
Heavy rain lead to a fallen tree across U.S. Highway 12 near milepost 52 and subsequent car accident at 4:08 am on the 5th. One person was injured in the incident and the highway was blocked for one and a half hours.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2018Every state in 2018This day in weather historyWarnings in Idaho, February 2018
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: 732640.