A disturbance moved across the Billings Forecast Area during the late morning hours on the 13th that resulted in severe thunderstorms that lasted into the early morning hours of the 14th.  Strong daytime heating along with 40-50 knots of southwesterly mid-level flow resulted in a very unstable atmosphere that was conducive for supercell thunderstorms.

Hail in SWEET GRASS, MONTANA
From 13-JUN-13 17:40:00 to 13-JUN-13 17:40:00 (MST-7)
Location: MELVILLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 13-JUN-13 17:40:00 to 13-JUN-13 17:40:00 (MST-7)
Location: ELSO
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 13-JUN-13 18:00:00 to 13-JUN-13 18:00:00 (MST-7)
Location: KLEIN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 13-JUN-13 18:15:00 to 13-JUN-13 18:15:00 (MST-7)
Location: DELPHIA
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GOLDEN VALLEY, MONTANA
From 13-JUN-13 18:30:00 to 13-JUN-13 18:30:00 (MST-7)
Location: RYEGATE ARPT
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GOLDEN VALLEY, MONTANA
From 13-JUN-13 19:05:00 to 13-JUN-13 19:05:00 (MST-7)
Location: LAVINA ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GOLDEN VALLEY, MONTANA
From 13-JUN-13 19:05:00 to 13-JUN-13 19:05:00 (MST-7)
Location: LAVINA ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 13-JUN-13 19:30:00 to 13-JUN-13 19:30:00 (MST-7)
Location: ROUNDUP
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CARBON, MONTANA
From 13-JUN-13 20:40:00 to 13-JUN-13 20:40:00 (MST-7)
Location: JOLIET
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Thunderstorm Wind in BIG HORN, MONTANA
From 13-JUN-13 21:50:00 to 13-JUN-13 21:50:00 (MST-7)
Location: KIRBY
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in ROSEBUD, MONTANA
From 13-JUN-13 22:40:00 to 13-JUN-13 22:40:00 (MST-7)
Location: LAME DEER
Magnitude: 58.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in CUSTER, MONTANA
From 13-JUN-13 23:10:00 to 13-JUN-13 23:10:00 (MST-7)
Location: GARLAND
Magnitude: 59.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

Thunderstorm Wind in CUSTER, MONTANA
From 14-JUN-13 03:09:00 to 14-JUN-13 03:09:00 (MST-7)
Location: MILES CITY
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Six inch tree limbs were down across areas of Miles City.

Hail in STILLWATER, MONTANA
From 13-JUN-13 18:24:00 to 13-JUN-13 18:24:00 (MST-7)
Location: REED PT
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in STILLWATER, MONTANA
From 13-JUN-13 10:12:00 to 13-JUN-13 10:12:00 (MST-7)
Location: RAPIDS
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in YELLOWSTONE, MONTANA
From 13-JUN-13 10:37:00 to 13-JUN-13 10:37:00 (MST-7)
Location: RIMROCK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in YELLOWSTONE, MONTANA
From 13-JUN-13 10:38:00 to 13-JUN-13 10:38:00 (MST-7)
Location: BILLINGS HGTS
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Golf ball size hail with wind gusts estimated at 60 mph was reported on the northwest side of Billings.

Thunderstorm Wind in YELLOWSTONE, MONTANA
From 13-JUN-13 10:38:00 to 13-JUN-13 10:38:00 (MST-7)
Location: RIMROCK
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Wind gusts of 60 mph were estimated along with golf ball size hail on the northwest side of Billings.

Hail in YELLOWSTONE, MONTANA
From 13-JUN-13 10:40:00 to 13-JUN-13 10:40:00 (MST-7)
Location: RIMROCK
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Half dollar size hail along with wind gusts estimated at 70 mph were reported.

Thunderstorm Wind in YELLOWSTONE, MONTANA
From 13-JUN-13 10:40:00 to 13-JUN-13 10:40:00 (MST-7)
Location: RIMROCK
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Thunderstorm wind gusts up to 70 mph along with half dollar size hail were reported just west of Billings.

Thunderstorm Wind in YELLOWSTONE, MONTANA
From 13-JUN-13 10:45:00 to 13-JUN-13 10:45:00 (MST-7)
Location: BILLINGS HGTS
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Thunderstorm wind gusts up to 60 mph along with dime size hail were reported on the northwest side of the Billings Heights.

Hail in PARK, MONTANA
From 13-JUN-13 13:40:00 to 13-JUN-13 13:40:00 (MST-7)
Location: SPRINGDALE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PARK, MONTANA
From 13-JUN-13 15:25:00 to 13-JUN-13 15:25:00 (MST-7)
Location: HUNTERS HOT SPGS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in SWEET GRASS, MONTANA
From 13-JUN-13 15:40:00 to 13-JUN-13 15:40:00 (MST-7)
Location: MELVILLE
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in SWEET GRASS, MONTANA
From 13-JUN-13 15:40:00 to 13-JUN-13 15:40:00 (MST-7)
Location: BIG TIMBER ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The hail was accompanied by 50 to 60 mph winds.

Thunderstorm Wind in SWEET GRASS, MONTANA
From 13-JUN-13 15:40:00 to 13-JUN-13 15:40:00 (MST-7)
Location: BIG TIMBER ARPT
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts estimated at 60 mph were reported.

Hail in PARK, MONTANA
From 13-JUN-13 16:15:00 to 13-JUN-13 16:15:00 (MST-7)
Location: WILSALL
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in STILLWATER, MONTANA
From 13-JUN-13 16:35:00 to 13-JUN-13 16:35:00 (MST-7)
Location: REED PT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in SWEET GRASS, MONTANA
From 13-JUN-13 16:15:00 to 13-JUN-13 16:15:00 (MST-7)
Location: GREYCLIFF
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts were estimated at 60 mph.

Hail in SWEET GRASS, MONTANA
From 13-JUN-13 16:35:00 to 13-JUN-13 16:35:00 (MST-7)
Location: MELVILLE
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in SWEET GRASS, MONTANA
From 13-JUN-13 16:40:00 to 13-JUN-13 16:40:00 (MST-7)
Location: BIG TIMBER ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in SWEET GRASS, MONTANA
From 13-JUN-13 16:40:00 to 13-JUN-13 16:40:00 (MST-7)
Location: BIG TIMBER ARPT
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts of 50 to 60 mph were estimated.

Hail in STILLWATER, MONTANA
From 13-JUN-13 16:55:00 to 13-JUN-13 16:55:00 (MST-7)
Location: REED PT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GOLDEN VALLEY, MONTANA
From 13-JUN-13 17:10:00 to 13-JUN-13 17:10:00 (MST-7)
Location: LAVINA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CARBON, MONTANA
From 13-JUN-13 17:10:00 to 13-JUN-13 17:10:00 (MST-7)
Location: BELFRY
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in PARK, MONTANA
From 13-JUN-13 17:20:00 to 13-JUN-13 17:20:00 (MST-7)
Location: HUNTERS HOT SPGS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in YELLOWSTONE, MONTANA
From 13-JUN-13 17:25:00 to 13-JUN-13 17:25:00 (MST-7)
Location: BROADVIEW
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in MUSSELSHELL, MONTANA
From 13-JUN-13 17:30:00 to 13-JUN-13 17:30:00 (MST-7)
Location: ELSO
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Flash Flood in MUSSELSHELL, MONTANA
From 13-JUN-13 18:00:00 to 13-JUN-13 22:59:00 (MST-7)
Location: KLEIN
Flood cause: Heavy Rain / Burn Area
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Several roads in the Dahl and Wilson Burn Scar areas were impacted by flash flooding, including Harper Coulee, Buckskin, Shortcut, Hampton, McCord and Aspen. Many private roads experienced significant erosion due to very heavy rainfall. Radar estimated 1 to 2 inches in an hour.