  We have identified 63 flares on M dwarfs from the individual component
spectra in the Sloan Digital Sky Survey using a novel measurement of emission
line strength called the Flare Line Index. Each of the ~38,000 M dwarfs in the
SDSS low mass star spectroscopic sample of West et al. was observed several
times (usually 3-5) in exposures that were typically 9-25 minutes in duration.
Our criteria allowed us to identify flares that exhibit very strong H-alpha and
H-beta emission line strength and/or significant variability in those lines
throughout the course of the exposures. The flares we identified have
characteristics consistent with flares observed by classical spectroscopic
monitoring. The flare duty cycle for the objects in our sample is found to
increase from 0.02% for early M dwarfs to 3% for late M dwarfs. We find that
the flare duty cycle is larger in the population near the Galactic plane and
that the flare stars are more spatially restricted than the magnetically active
but non-flaring stars. This suggests that flare frequency may be related to
stellar age (younger stars are more likely to flare) and that the flare stars
are younger than the mean active population.
