  Recently it was shown in Ref. [Phys. Rev. Lett. 112, 140402 (2014)] that in
the idealized Dicke model of superradiance there is no entanglement among any
partitions of the system during the total evolution time of the system. This
result immediately conducts us to question if other measures from quantum
information theory can explain the characteristic release of energy in a short
time interval. In this work we identify the uncertainty of purely quantum
origin as the property responsible for Dicke superradiance. The quantum
uncertainty on the population of each emitter of the sample captured by the
Wigner-Yanase skew information (WYSI) is proportional to the correlation
radiation rate, which is the part of the total radiated power coming from
dipole correlations and responsible for releasing in a short time a great
intensity of radiation energy. We also show that the correlation measure called
local quantum uncertainty, which is the minimization of the WYSI over all local
observables, presents a double sudden change induced by environment. The time
window between these two sudden changes is used to define the interval in which
symmetric global observables of the system behave classically for $N
\rightarrow \infty$, although the emitters remain strongly quantum correlated.
