  We carried out intensive spectroscopic observations of two WZ Sge-type dwarf
novae, GW Lib, and V455 And during their superoutbursts in 2007, at 6
observatories. The observations covered the whole of both superoutbursts from
the very maximum to the fading tail. We found evidence of the winds having a
speed of $\sim$1000 km s$^{-1}$ which blew in GW Lib during the rising phase.
The evolution of the hydrogen, helium, and carbon lines suggests flaring of the
accretion disk and emergence of the temperature inversion layer on the disk.
