The energy transfer rate between the lattice and electrons in strongly
nonequilibrium electron-phonon system of crystalline aluminum created by
ultrashort femtosecond laser pulse is calculated in the frame of
two-temperature model for a wide range of electron temperature. It is
shown that the energy, transmitted from electrons to the lattice per unit
volume of the crystal per unut time strongly increases when taking into
account the umklapp processes in the electron-phonon scattering.