Idaho, 2015Avalanche in Idaho, January 18, 2015
January 18, 2015 · NWS MSO · 1 event in 1 county or zone
An atmospheric river brought periods of moderate to heavy rain and snow and strong gusty winds to the higher elevations of Lemhi County between Jan 17 and 18. This led to the first avalanche cycle south of Lost Trail Pass.
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- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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 atmospheric river brought periods of moderate to heavy rain and snow and strong gusty winds to the higher elevations of Lemhi County between Jan 17 and 18. This led to the first avalanche cycle south of Lost Trail Pass.
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 Jan 18, 3:52 AM MST, 1 hour 8 minutes earlier.
Area forecast discussion, Jan 18, 3:52 AM MST, 1 hour 8 minutes before
Area Forecast Discussion
National Weather Service Missoula MT
352 AM MST SUN JAN 18 2015
.DISCUSSION...
Snow has already fallen across central Idaho and most of western
Montana. The main surge of moisture is clearly seen this morning
on radar entering the Idaho panhandle. This main surge of moisture
will bring higher snow levels with it causing the snow to change
to rain for a least a few hours this morning at most passes,
except Lost Trail pass.
Then as the cold front passes late this morning snow levels will
begin to fall again. When this happens road conditions will likely
deteriorate quickly as the slush, wet snow, and rain refreeze on
the road during the afternoon. Precipitation will decrease rapidly
behind the front, turning to snow at the passes and becoming light
and showery.
Weak shortwaves within the northwesterly flow will keep light
showers around till Tuesday. Valley fog will also be possible
especially over northwest Montana and north central Idaho Tuesday
morning due to the abundant moisture from this weekend's rain and
snow. More widespread fog or low clouds will be possible on
Wednesday and Thursday mornings as high pressure builds in over
the region. During this time high clouds will stream over the
area, which could help prevent dense fog from forming.
Beyond Thursday, models are continuing to show a weak disturbance
moving in Thursday night into Friday. This could bring a period of
light snow to northwest Montana.
&&
.AVIATION...Radar shows a plume of moisture entering the Panhandle
of Idaho this morning which will work its way across western
Montana this morning. Expect low ceilings to continue at KMSO and
KGPI through the morning, until the cold front passes late this
morning around 18Z. Colder, dry air behind the front will break up
the clouds some and cause the precipitation to decrease quickly
and become showery. Until the cold front passes, periods of
freezing rain are possible at KSMN, KMSO, and KGPI.
&&
.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 11 AM MST this morning ABOVE 4500
FEET for the Bitterroot/Sapphire Mountains...Lower Clark
Fork Region.
WINTER WEATHER ADVISORY until 11 AM MST this morning
Flathead/Mission Valleys...Kootenai/Cabinet Region...West
Glacier Region.
ID...WINTER WEATHER ADVISORY until 10 AM PST this morning ABOVE 4500
FEET for the Southern Clearwater Mountains.
&&Avalanche, Eastern Lemhi County
- When
- January 18, 5:00 AM MST to 1:00 PM MST
- Where
- Eastern Lemhi County forecast zone
- Reported by
- Department of Highways
- Coordinates
- 44.943, -113.933 (the zone’s center; the record gives no point)
A foreman with the Idaho Transportation Department reported that 13 avalanches occurred during this period. One of them crossed both lanes of US-93 at milepost 349.5. and was 12 feet high, 110 feet long and 12 feet wide. It took around 1 hour to clear one lane and another 2 hours to clear the remaining snow.
- Avalanche
- A mass of snow sliding down a mountainside that caused a death, an injury or damage.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Winter Weather in Pennsylvania, January 18, 20153 deaths · 100 injured · 13 events
- Winter Weather in New Jersey, January 18, 20152 deaths · 32 injured · 10 events
- Winter Weather in Maryland, January 18, 20152 deaths · 9 injured · 6 events
- Winter Storm and Winter Weather in Vermont, January 18 to 19, 20152 deaths · $215,000 · 12 events
- Winter Weather in Connecticut, January 18, 20151 death · 8 events
- Winter Weather in Massachusetts, January 18, 20151 injured · $220,000 · 8 events
- Tornado in Washington, January 18, 2015EF1 · 1 event
- Flooding and Winter Weather in New York, January 18, 201515 events
- Flood and Winter Weather in New Jersey, January 18, 201510 events
- Winter Weather in New York, January 18 to 19, 20159 events
- Flooding and Heavy Rain in New Jersey, January 18 to 20, 20155 events
- Winter Weather in Vermont, January 18 to 19, 20153 events
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: 551411.