Montana, 2015Heavy Rain in Montana, February 7 to 12, 2015
February 7 to 12, 2015 · NWS MSO · 3 events in 3 counties and zones
An exceptionally strong atmospheric river brought up to 3 inches of precipitation and well-above normal temperatures to the region. Record-breaking temperatures into the 50s occurred in many valley locations.
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- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
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- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 3
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.
An exceptionally strong atmospheric river brought up to 3 inches of precipitation and well-above normal temperatures to the region. Record-breaking temperatures into the 50s occurred in many valley locations. An unusually high number of roadway rockslides was reported.
What forecasters said that day
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 7, 3:55 AM MST, 5 minutes earlier.
Area forecast discussion, Feb 7, 3:55 AM MST, 5 minutes before
Area Forecast Discussion
National Weather Service Missoula MT
355 AM MST SAT FEB 7 2015
.DISCUSSION...
Some light bands of precipitation are spreading along the Idaho
and Montana border this morning with relatively high snow levels
continuing above 6000-7000ft. After a warm mix-out day yesterday,
majority of the valleys currently remain well above normal this
morning in the 30s to low 50s. High temperatures may not reach
quite as warm today as they did yesterday with slightly less
mixing expected and an increase of moisture aloft, but above
normal temperatures will surely be likely with some max
temperatures potentially coming close to records.
An enhanced wave of precipitation accompanied with a warm front
will spread over north central Idaho and western Montana later
this morning which will may allow for some previously shadowed
valley regions to receive measurable rainfall throughout the
morning hours. Westerly winds aloft will once again increase over
the afternoon and will encourage downsloping effects that were
noticed yesterday. Lingering showers over the region will last
through tonight and potentially early Sunday before diminishing by
midday Sunday with a break lasting through very early Monday
morning.
The next storm system will quickly approach the region Monday.
Although it doesn't possess nearly the amount of moisture
expected this weekend, it will bring another dose of steady
rainfall to the Northern Rockies. The snow level should begin to
fall Monday night as a cold front pushes through the region. Rain
will transition to snow over many mountain passes and may produce
some minor impacts to travel. There is still a chance that the
snow level may descend even farther Tuesday night with possibility
of robust post-frontal showers bringing snow back to some western
Montana valleys.
From Wednesday on, all models show unseasonably strong high
pressure settling in across the region. There are hints that the
high pressure may be a bit weaker than previously thought with
perhaps some moisture passing through the flow in the form of
clouds and/or very light precipitation. However this does little
to dissuade against a forecast of persistent fog in the valleys
where snow remains and unseasonably warm temperatures in the
snow-less valleys.
&&
.AVIATION...Minimal impacts from rain and wind are expected at
KGPI, KMSO, KBTM and KSMN through the next 24 hours. However,
showers in the vicinity of most air fields will obscure terrain at
times.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&
Heavy Rain, Mineral
- When
- February 7, 4:00 AM MST to February 9, 12:00 PM MST
- Where
- Mineral County, 2.69 mi NW of Henderson
- Reported by
- Department of Highways
- Coordinates
- 47.348, -115.290
Heavy rain caused a rockslide on February 7th that closed the westbound lanes of I-90 west of St Regis, MT. Several hundred small rocks and boulders had to be cleared from the road surface. No accidents were reported. Westbound lanes were closed for 2 days as traffic was forced to divert to the north via MT Hwy 135 and MT Hwy 200, thus increasing travel distance. By the afternoon of Feb 9th, one lane, two-way traffic had been set-up, ending the interstate re-route.
Heavy Rain, Missoula
- When
- February 10, 5:30 AM MST to February 12, 3:45 PM MST
- Where
- Missoula County, 8.58 mi ENE of Lolo Hot Spgs
- Reported by
- Department of Highways
- Coordinates
- 46.773, -114.360
Heavy rains led to a large boulder falling and blocking the west-bound lane of US-12 during the early morning hours of February 10th, 2015. The slide happened 14 miles west of Lolo, MT. The mountain pass road was closed to any through-traffic for over a day and a half as officials hired a crew to inspect, blast, and remove large rocks. Truckers reported losing thousands of dollars per day as they could not use the route. Road crews noted that this is one of the largest slides they could recall. Full traffic flow resumed 2 days later.
Heavy Rain, Flathead
- When
- February 10, 6:35 PM MST to 7:44 PM MST
- Where
- Flathead County, 1.28 mi E of West Glacier
- Reported by
- Department of Highways
- Coordinates
- 48.500, -113.942
A rockslide was reported along US-2 just east of West Glacier, MT. The eastbound lane was blocked by softball-sized rocks. Road crews cleared debris and the road was usable again an hour later.
- Heavy Rain
- Rainfall totals unusual for the place and season that did not produce a flood.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Heavy Snow and Winter Weather in New York, February 7 to 10, 201527 events
- Heavy Snow in New Hampshire, February 7 to 10, 201510 events
- Winter Storm in Alaska, February 7 to 8, 20155 events
- High Wind in Oregon, February 7, 201570 kt wind · 3 events
- Heavy Snow in Vermont, February 7 to 10, 20153 events
- Debris Flow and Flooding in Idaho, February 7 to 9, 20153 events
- Heavy Snow and Winter Weather in Massachusetts, February 7 to 10, 20152 events
- Heavy Snow and Winter Weather in Connecticut, February 7 to 10, 20152 events
- Flood in California, February 7 to 8, 20151 event
- Flood in Oregon, February 7 to 10, 20151 event
- High Wind in Wyoming, February 7, 201561 kt wind · 1 event
- High Wind in Washington, February 7, 201556 kt wind · 1 event
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: 554468, 554456, 554445.