National Weather Service United States Department of Commerce


#11 Berthoud, Colorado Tornado 

June 4th, 2015 Berthoud, Colorado


On the evening of June 4th, 2015 a rare EF3 tornado, with estimated wind speeds up to 140 mph, tracked almost due west along the Boulder, Larimer county line.  The tornado was a quarter mile wide, at times, and had a path length of 6 miles.  This is the strongest tornado on record, that has affected Boulder and Larimer counties, since official ratings began in 1950.  28 homes were damaged with three being destroyed.  Fortunately, there were only a few minor injuries and no deaths.


Tornado track and intensity based on NWS Storm Survey


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

Video of Tornado courtesy of Cory Reppenhagen


Reflectivity Loop at 0.5 Degrees


Storm Relative Velocity Loop at 0.5 Degrees


Damage pictures near the Boulder/Larimer county line