Unseasonably warm temperatures occurred in the first two weeks of April, with highs near 80 degrees occurring at times. These warm temps, along with occasional rain, resulted in melting of a deep snowpack on top of frozen ground which led to significant runoff into area waterways. Moderate to major flooding occurred along portions of the Milk River and its tributaries. Impactful snowmelt flooding also occurred across Southcentral Montana, in particular across the Gallatin Valley.

Flood in HILL, MONTANA
From 12-APR-23 00:00:00 to 14-APR-23 00:00:00 (MST-7)
Location: LAREDO
Flood cause: Heavy Rain / Snow Melt
Property damage: 2.00M
Crop damage: 500.00K
Reported by: River/Stream Gage

Mountain snowpack in the Milk River basin melted out very quickly and contributed significant flooding. Virtually the entire Milk River system flooded in a matter of days as a result, starting near the headwaters in Hill County. Big Sandy Creek near Havre crested at 12.07 feet on April 13, which (as of entry) was the fourth highest crest on record. Route 50 was greatly flooded as well as some businesses . Farther north, Lodge Creek below McRae Creek  approached Major Flood stage before cresting at 10.59 feet on April 18th. Much of rural northern Hill County experienced flooding as a result. The Milk River gauge near Havre remained below flood stage, although river levels did come out of their banks farther east, ultimately impacting eastern portions of Havre.

Flood in BLAINE, MONTANA
From 10-APR-23 00:00:00 to 14-APR-23 00:00:00 (MST-7)
Location: CHINOOK
Flood cause: Heavy Rain / Snow Melt
Property damage: 1.00M
Crop damage: 500.00K
Reported by: River/Stream Gage

Significant flooding occurred along the Milk River across Blaine County. The Rocky Boy SNOTEL station which is the main Milk River basin station peaked later than normal and had over 3.5 times the snow water equivalent that it normally would on April 6 (10.7��� of snow water equivalent versus a normal of 3.0���). When this thick snowpack melted, virtually the entire Milk River system flooded in a matter of days, as a result. The Milk River near Harlem crested at 23.80 feet on April 12, which as of this entry was the seventh highest river level recorded at this site. Roughly 4,000 aces of irrigation land was flooded. Chinook water plant was surrounded by water. Several roads and homes were impacted.

Flood in BEAVERHEAD, MONTANA
From 10-APR-23 00:00:00 to 13-APR-23 18:00:00 (MST-7)
Location: DEWEY
Flood cause: Heavy Rain / Snow Melt
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Meagher County Sheriff's office stated rockslides were occurring in the Deep Creek Canyon area, affecting Highway 12, due to snowmelt and flooding.

Flood in BLAINE, MONTANA
From 08-APR-23 00:00:00 to 10-APR-23 00:00:00 (MST-7)
Location: LOHMAN
Flood cause: Heavy Rain / Snow Melt
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

Significant snowmelt resulted in flooding along Battle Creek, near Chinook. The creek crested on April 12th at 11.94 feet. Several roads across northern and central Blaine County were impacted as a result. Water was reported over Highway 2, west of Chinook, for a time. Runoff from Cypress Hills in southern Canada may have contributed to the flooding.

Flood in LIBERTY, MONTANA
From 07-APR-23 00:00:00 to 12-APR-23 00:00:00 (MST-7)
Location: LOTHAIR
Flood cause: Heavy Rain / Snow Melt
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Roads north of Lothair become flooded from snowmelt. Liberty Co law enforcement closed several sections of several roads across the county.

Flood in BLAINE, MONTANA
From 07-APR-23 20:00:00 to 14-APR-23 00:00:00 (MST-7)
Location: LLOYD
Flood cause: Heavy Rain / Snow Melt
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

Significant snowmelt resulted in flooding along Clear Creek. The creek rose approximately four feet over a 24 hour period from April 8th to April 9th, before dramatically subsiding. A nearby reservoir about 3 acres in size filled and flooded within five hours. The river gauge for Clear Creek near Chinook crested at 8.12 feet, with 8.00 feet being the designated beginning of Major Flood Stage. Multiple nearby roads were flooded as a result.

Flood in GALLATIN, MONTANA
From 10-APR-23 00:00:00 to 13-APR-23 18:00:00 (MST-7)
Location: CHESTNUT
Flood cause: Heavy Rain / Snow Melt
Property damage: 1.00M
Crop damage: 0.00K
Reported by: Emergency Manager

Churchill area saw pretty good runoff occur. Several locations around Amsterdam (Camp and Godfrey Creeks) had water up against houses. The Highline Canal near Gallatin Gateway overtopped in several locations due to runoff.  One house and Axtell Anceny Road were affected. Residents on Dry Creek Road and Swamp Creek Road had flood water around houses.  This caused the evacuation of the Bootstrap Ranch. County Roads had several roads closed with water on them.

Flood in CHOUTEAU, MONTANA
From 11-APR-23 00:00:00 to 13-APR-23 00:00:00 (MST-7)
Location: BIG SANDY ARPT
Flood cause: Heavy Rain / Snow Melt
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Chouteau County Sheriff's Office reported flood-related closures in Big Sandy at North Lonesome Lake Road between Ihmsen Well Road and Gardiner Road and from Black Coulee Road to Rudyard Road.

Flood in LEWIS AND CLARK, MONTANA
From 09-APR-23 00:00:00 to 11-APR-23 00:00:00 (MST-7)
Location: BIRDSEYE
Flood cause: Heavy Rain / Snow Melt
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Lewis and Clark County Sheriff's Office reported the high bridge over the Dearborn River was washed out. Public works closed the road at Flat Creek. Several secondary roads across the area were flooded at times. Flooding across northwest Helena also occurred, especially west of Birdseye Road.