Montana, 2018

Winter Storm in Montana, April 1 to 3, 2018

April 1 to 3, 2018 · NWS GGW · 3 events in 3 counties and zones

A strong late-season winter storm moved across the northern Rockies from the Pacific Northwest on the evening of the 1st, bringing gusty winds and accumulating snow to areas mainly south of the Missouri River through the 2nd. The heaviest snowfall occurred across Garfield and Petroleum counties, where four to six inches of snow was reported.

Where it happened

Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

  • Tornadoes
  • Tropical storms and surge
  • Floods
  • Wind
  • Hail
  • Winter weather
  • Heat and drought
  • Cold
  • Fire, smoke and dust
  • Marine and coastal
  • Other

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The toll

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.

What happened

The episode as NWS GGW wrote it up.

A strong late-season winter storm moved across the northern Rockies from the Pacific Northwest on the evening of the 1st, bringing gusty winds and accumulating snow to areas mainly south of the Missouri River through the 2nd. The heaviest snowfall occurred across Garfield and Petroleum counties, where four to six inches of snow 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 Glasgow, MT wrote its last area forecast discussion before the first event at Apr 1, 1:23 PM MST, 3 hours 37 minutes earlier.

Area forecast discussion, Apr 1, 1:23 PM MST, 3 hours 37 minutes before
Area Forecast Discussion
National Weather Service Glasgow MT
223 PM MDT Sun Apr 1 2018

.DISCUSSION...

This week's progressive pattern begins with a low pressure system
churning over southern BC this evening. This system will send
plenty of moisture over the Divide tonight where it will meet a
cold boundary that will be backed up by the Hudson Bay Arctic
low. The trough moves east through Montana through Monday evening
while the Arctic low pushes south. With plenty of QPF and cold
air, significant amounts of snow can be expected in some
locations, mainly our southwest and southern zones. Surface
pressure gradients will also generate winds at times, resulting in
blowing and drifting snow. Temperature profiles suggest the
possibility of rain/freezing rain at times.

Hazards: Inherited WSW for Petroleum & SW Phillips, starting this
evening. Changed Winter Storm Watch to segmented WSW and Winter Wx
Advsry. Southern counties were added to the WSW. Elsewhere to the
Advsry. Continued to leave out Daniels and Sheridan Counties. All
end either at 06Z Tuesday or 12Z Tuesday.

Tuesday and Wednesday, the upper ridge returns, keeping the area
dry, even though the cold boundary will keep temperatures below
normal.

Thursday, precipitation chances return by way of another Arctic
front and overriding moisture from the Pacific Northwest. Most
model guidance again brings less snow to local areas along the
Canadian border. From here on out, there are the normal model
discrepancies, so continued with the latest model blends. Looks
like unsettled weather from Thursday through the weekend with a
couple more systems moving through. We will be able to get more
detailed over the next few days.

Templer

&&

.AVIATION...

Expected Flight Category: VFR into this evening. Expect
restrictions by Monday morning due to another winter storm system
that should continue through Monday evening..

Synopsis: Another approaching winter storm system moves in this
evening and could hinder operations through Monday.

Wind: Light and variable today. late afternoon, winds will shift
to the east southeast at 7-12 kts across the sites. After midnight,
winds will become east northeasterly at 15-20 kts.

SCT

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from midnight tonight to midnight MDT
Monday night for Eastern Roosevelt...Northern Phillips...
Northern Valley...Richland...Western Roosevelt.

Winter Storm Warning from 6 PM this evening to midnight MDT
Monday night for Petroleum...Southwest Phillips.

Winter Storm Warning from midnight tonight to 6 AM MDT Tuesday
for Prairie...Wibaux.

Winter Storm Warning from midnight tonight to midnight MDT
Monday night for Central and Southeast Phillips...Central and
Southern Valley...Dawson...Garfield...McCone.

&&

weather.gov/glasgow

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

3 winter storm. Local standard time, as filed.

Winter Storm, Petroleum

When
April 1, 5:00 PM MST to April 2, 10:00 PM MST
Where
Petroleum forecast zone
Reported by
Department of Highways
Coordinates
47.118, -108.250 (the zone’s center; the record gives no point)

This storm began with rain on the evening of April 1st. As temperatures dropped overnight, the precipitation transitioned to snow, and the Montana Department of Transportation observed roads were snow covered and icy. Additionally, winds gusting to 25 to 30 mph were causing travel difficulties across Petroleum County. These conditions persisted into the evening of April 2nd. Snowfall totals from cooperative observers in this storm ranged from 4 inches at Winnett 12 SW to 8 inches at Flatwillow 4 ENE.

Winter Storm, Little Rocky Mountains

When
April 1, 5:00 PM MST to April 2, 10:00 PM MST
Where
Little Rocky Mountains forecast zone
Reported by
Department of Highways
Coordinates
48.259, -107.913 (the zone’s center; the record gives no point)

This storm began with rain on the evening of April 1st. As temperatures dropped overnight, the precipitation transitioned to snow, and the Montana Department of Transportation observed roads were snow covered and icy by the morning of the 2nd. Additionally, winds gusting to 25 to 30 mph were causing travel difficulties across the Little Rockies and southwestern Phillips County. These conditions persisted into the evening of April 2nd. Snowfall totals from this storm ranged from 2 to 4 inches.

Winter Storm, Garfield

When
April 1, 9:00 PM MST to April 3, 3:00 AM MST
Where
Garfield forecast zone
Reported by
COOP Observer
Coordinates
47.278, -106.993 (the zone’s center; the record gives no point)

Snow began falling across southwest Garfield County at approximately 9 PM MST on the night of April 1st. By around 11 AM MST on the 2nd, 4 to 6 inches of snow had fallen across much of Garfield County. Additionally, blowing and drifting snow were causing travel difficulties, especially along Highway 200. The storm slowly moved out of the area late on the 2nd.

What these are

Winter Storm
A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Montana in 2018Every state in 2018This day in weather historyWarnings in Montana, April 2018

Sources

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: 747414, 747416, 747428.