According to a preliminary survey, the National Weather Service has confirmed an EF-1 tornado at Shooting Star Casino in Mahnomen, MN early Monday morning.
The tornado is estimated to have had a path of 400 yards and a width of 30 yards.
The winds were estimated around 90-95 MPH which puts it in the EF-1 category.
No injuries were reported.
This is a preliminary survey and more information will be released once the complete survey is completed.
Here is the survey text from the National Weather Service:
...PRELIMINARY NWS DAMAGE SURVEY FOR MAHNOMEN COUNTY TORNADO EVENT...

RATING: EF-1
ESTIMATED PEAK WIND: 90-95 MPH
PATH LENGTH /STATUTE/: 400 YARDS
PATH WIDTH /MAXIMUM/: 30 YARDS

START DATE: 06/22/2015
START TIME: 226 AM CDT (ESTIMATED)

SURVEY SUMMARY: VERY PRELIMINARY RESULTS FROM THE NWS DAMAGE
ASSESSMENT INDICATED A BRIEF TORNADO OCCURRED NEAR THE SHOOTING
STAR CASINO IN MAHNOMEN...MINNESOTA. FURTHER DETAILS WILL BE
PROVIDED ONCE THE SURVEY IS COMPLETED.

EF SCALE: THE ENHANCED FUJITA SCALE CLASSIFIES
TORNADOES INTO THE FOLLOWING CATEGORIES.

EF0...WEAK......65 TO 85 MPH
EF1...WEAK......86 TO 110 MPH
EF2...STRONG....111 TO 135 MPH
EF3...STRONG....136 TO 165 MPH
EF4...VIOLENT...166 TO 200 MPH
EF5...VIOLENT...>200 MPH

NOTE:
THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO
CHANGE PENDING FINAL REVIEW OF THE EVENT AND PUBLICATION IN
NWS STORM DATA.