A surface low centered over far southern Montana and northern Wyoming was able to pull a cold front across northeast Montana on the evening of the 30th. This, in addition to the presence of northwest flow aloft and mid-level moisture advection, produced snow showers across the area.
Every event with a place to put it; 1 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 GGW wrote it up.
A surface low centered over far southern Montana and northern Wyoming was able to pull a cold front across northeast Montana on the evening of the 30th. This, in addition to the presence of northwest flow aloft and mid-level moisture advection, produced snow showers across the area. Although only a few inches of snow fell during this time, gusty winds developed in response to a strong pressure gradient associated with the surface low. As a result, blowing and drifting snow began to impact driving conditions along the Canadian border where winds were stronger.
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 Mar 30, 9:18 AM MST, 3 hours 42 minutes earlier.
Area Forecast Discussion...UPDATED National Weather Service Glasgow MT 1018 AM MDT Fri Mar 30 2018 .DISCUSSION... Radar and satellite imagery both show a wave in the northwest flow that is riding across a distinct cold front stretching across Northeast Montana. The cold front will continue moving south as colder Arctic air slips in behind the it. Overrunning moisture seems to be focused over our northeast corner this morning, but light snow has fallen elsewhere. Models show two quick waves, back-to-back. The second wave this afternoon will become more widespread with the snow and rain. The Storm Prediction Center's Convective outlook for today spreads into the extreme southern areas of Petroleum and Garfield Counties for general thunderstorms today. So a few lightning stikes will be possible. East wind has also ramped up and will strengthen further, and back around to the north later today. This will likely cause blsn and more lowering of visibility. Temperature readings this morning at 1430Z appear to be below freezing across the entire CWA, and in single digits in the northeast corner of Sheridan County. Temperatures will warm up enough across southern zones for rain initially. But as the front continues south, the rain will turn to snow this afternoon. There is a combination of a winter storm warning for Sheridan County, and winter wx advsry for the rest of the northern tier, and the Hi-Line east of Phillips County through 06Z tonight. Hydrology issues from melting snow continue. refer to the Hydrology Discussion below. The inherited forecast was in good shape. Edits were minor, based on the latest near term guidance. Templer Previous Discussion: A large low pressure system over the Hudson Bay region and a shortwave moving across Alberta and Saskatchewan and into Montana are the driving forces behind the latest winter storm. Precipitation is already occurring across portions of northeast Montana this morning, and this will continue throughout the day. Snowfall amounts should be in the order of 3 to 5 inches, and the majority of this is expected to fall before this evening. Additionally, strong winds of up to 35 to 40 mph are expected to blow the snow around significantly reducing visibility, at least through midnight when the winds should diminish. As a result, there is a Winter Storm Warning in Sheridan County until midnight tonight due to a combination of snowfall and blowing snow. Considered adding Daniels and Roosevelt Counties to the warning due to blowing snow concerns, but left the existing advisories in place as the impacts from the blowing snow do not look to be quite as severe as in Sheridan County, although visibilities will be reduced there as well. High temperatures will only manage to make it into the teens to perhaps the mid 20s along much of the Canadian border where the highest snowfall amounts are expected, but into the 40s further south. As the system moves out of the region tonight, northwest flow will push colder air into the region. Overnight lows tonight will drop into the single digits above and below zero, with wind chills approaching or dropping to less than 20 below zero along and north of the Hi-Line. This overall pattern will not change much as the low pressure will still be locked over the Hudson Bay region. Another system is anticipated to move through the area Monday, although currently much lower snowfall amounts are in the forecast. Temperatures will finally begin to make a slow recovery beginning around mid-week. Hickford && .AVIATION... FLIGHT CAT: ranging from VFR to IFR. SYNOPSIS: A clipper-like winter storm slides southeast through the region today, bringing wide spread light snow, blowing snow, and rain. Reduced flight conditions and amendments are expected from this storm. A surface high will move in behind the storm tonight, ending precipitation, but maintaining low VFR/MVFR overcast. WIND: East-southeast at 10 to 20 kts this morning. Backing to the northeast and increasing to 15 to 25 kts this afternoon, then north at 15 to 25 kts after 00Z this evening. Diminishing to less than 10kt after midnight when the surface high moves in. && .HYDROLOGY... Some flooding concerns persist across portions northeast Montana, due to ice jams and snowmelt. Colder weather over the next week will slow snow and ice melt. A small stream flood advisory continues for Petroleum County due to poor drainage areas continuing to fill up with meltwater. The portion of the Yellowstone River in eastern Montana has cleared, as any remaining ice jams have moved into North Dakota. The flood warning there has now been cancelled. Areal Flood Advisories are in effect for Beaver Creek and Peoples Creek in Phillips county. Snow melt due to the recent warm temperatures has finally begun to bring fresh water to these creeks. They and their surrounding tributaries will run higher into the weekend. Willow Creek in Valley county has also begun to run and is bringing rises to water levels on the Milk River just east of Glasgow. No flooding is occuring or anticipated at this time on the Milk River in Valley county. To monitor river stage readings, go to our Advanced Hydrologic Prediction Service (AHPS) page at www.weather.gov/glasgow then click on "Rivers and Lakes" then "River Observations". Data for this page are provided by the USGS. && .GLASGOW WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until midnight MDT tonight for Central and Southern Valley...Daniels...Eastern Roosevelt...Northern Phillips...Northern Valley...Richland...Western Roosevelt. Winter Storm Warning until midnight MDT tonight for Sheridan. && weather.gov/glasgow
The national radar mosaic for the moment the first event began.
1 winter storm. Local standard time, as filed.
The Montana Department of Highways archived road reports show that significant blowing and drifting snow created hazardous driving conditions across Sheridan County during the afternoon and early evening hours of March 30th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2018Every state in 2018This day in weather historyWarnings in Montana, March 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: 746923.