Unique structural fluctuations at ice surface promote autoionization of water molecules
(PHYSorg.com Chemistry)

Water ice is one of the most abundant solid substances in nature and hydrated protons on ice surfaces critically influence physical and chemical properties of ice. Hydrated protons are easily doped into the hydrogen-bond (HB) networks when acidic impurities are present. In contrast, in pure water molecular systems, they are generated solely by the thermal ionization of water molecules (H2O