  The near-ultraviolet and optical (white-light) continuum radiation in M dwarf
flares exhibits a range of observed characteristics, suggesting that the amount
of heating at large optical depth varies among impulsive-type and gradual-type
flares. Specific flux ratios from high-time cadence spectra and narrowband
continuum photometry have also shown that these characteristics vary from the
peak to the gradual decay phases of flares. In these proceedings, we present
the highest-time cadence ($\sim1$~s), highest signal-to-noise ($\sim100$)
constraints on the optical color temperature evolution during the rise phase of
a large, impulsive-type dMe flare event. The flare exhibits compelling evidence
of a hot, color temperature ($T \sim 10,000$ K), but the Balmer jump ratios
show that the flare cannot be explained by isothermal slabs or blackbody
surfaces at any time in the evolution. The new data analysis establish these
properties as critical challenges for any flare model, and we discuss 1D
radiative-hydrodynamic modeling that will be compared to the evolution of the
flare colors in this intriguing event.
