Montana, 2018

Flood in Montana, April 25 to 30, 2018

April 25 to 30, 2018 · NWS GGW · 1 event in 1 county or zone

Warming temperatures led to river flooding along the lower Milk River beginning during the latter part of April. Flooding had already been occurring on the Milk River and some of its tributaries upstream since April 16th, and flooding on the lower Milk River began on the 25th.

Where it happened

Every event with a place to put it. Tap one for its entry below.

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  • Floods
  • Wind
  • Hail
  • Winter weather
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  • Cold
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The toll

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.

What happened

The episode as NWS GGW wrote it up.

Warming temperatures led to river flooding along the lower Milk River beginning during the latter part of April. Flooding had already been occurring on the Milk River and some of its tributaries upstream since April 16th, and flooding on the lower Milk River began on the 25th. Flooding continued into the early part of May.

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 25, 8:09 PM MST, 21 minutes earlier.

Area forecast discussion, Apr 25, 8:09 PM MST, 21 minutes before
Area Forecast Discussion...UPDATED
National Weather Service Glasgow MT
909 PM MDT Wed Apr 25 2018

.DISCUSSION...

9PM Update: Re-freshed the now to near term forecast grids with
the latest observation data and the best model consensus data.
Isolated rain showers will gradually diminish away toward the SE
through the overnight hours with clearing skies from the NW.
Gustier winds from earlier today will also diminish through the
overnight hours.          BMickelson

Cold front moving through this afternoon will generate wind gusts
to 35 mph, then some scattered light showers moving SE through
the area this evening. Winds shouldn't be anything like what we
saw on Saturday, as inverted-v sounding is not in the cards thanks
to the thick veil of clouds overhead today.

Afterwards, a sharp upper ridge drifts east and allows for a
warming trend with plenty of sunshine. Look for temperatures to
rise to well above normal levels by Saturday.

Then a large closed Pacific system will move in from the Pacific
NW and bring healthy instability to the area by Sunday. The ECMWF
shows CAPES over 1000 J/kg to the area, while the GFS is further
east with this axis.

Cooler and marginally wet conditions can be expected for the
balance of early next week. Look for high temperatures to drop
back to below normal levels. TFJ

&&

.AVIATION...

Expected Flight Category: VFR

Weak cold front now through the region will support a few more
isolated rain showers overnight, moving SE, then winds and clouds
will dissipate later tonight. TFJ/BLM

&&

.HYDROLOGY...

Flood warnings remain in effect for the Milk River and its
tributaries until further notice.

The Milk River continues to slowly rise from Tampico through
Nashua. The main concern is from Saco to Glasgow where Moderate
Flood Stage is expected to hold through most of next week.

Multiple flood warnings continue for river forecast points along
the lower Milk River.

Local reports indicate that the Frenchman Creek continues to
recede. The flood advisory there has been cancelled.

Water levels on Beaver Creek continue to drop but with high water
around Saco the Flood Warning remains in effect.

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...NONE.

&&

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

1 flood. Local standard time, as filed.

Flood, Valley

When
April 25, 8:30 PM MST to April 30, 11:59 PM MST
Where
Valley County, 1.26 mi W of Nashua to 1.95 mi ENE of Nashua
Cause
Heavy Rain / Snow Melt
Reported by
River/Stream Gage
Coordinates
48.131, -106.377

Excessive snow melt caused flooding at the river gauge on the Milk River near Nashua (NSHM8). The gauge recorded river levels reaching flood stage at 8:30 PM MST on April 25th. The river crested at 22.35 feet at 2:15 PM MST on April 30th. River levels remained at or above flood stage into May.

What these are

Flood
Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

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: 748818.