The Manheim-Hudec scale is a scale measuring the intensity of changes in the space-time continuum. The scale reads from 0 to 10, with 10 resulting in the destruction of the known universe. The scale was created by Drs. Paul Manheim and Hudec.
In 2373, when the Borg invaded the Federation, the USS Enterprise-E encountered a disturbance of a magnitude of 7.83 on the Manheim-Hudec scale, which saw the Borg in control of Earth and the majority of the Alpha Quadrant. (Star Trek: First Contact)
In the same year, as a result of the same event, the USS Cantabrian shuttlecraft away team, led by Noah Wrightston, encountered the same disturbance that threw them into the mid-2270s. This event had a disturbance of the magnitude of 6.2208 on the scale. (Star Trek: The Cantabrian Expeditions: "The Fire In Which We Burn")