In this article, the liquid water eruptive transport occurring during the water breakthrough from the Gas Diffusion Layer (GDL) of a PEMFC into the gas channel is investigated. A dedicated experimental set-up is used enabling the simultaneous measurement of pressure inside the water system and visualization of droplet formation. A single-drop capillary model is proposed to explain the eruptive nature of droplet formation. The model is built on four physical equations involving Laplace's law, a water system compressibility law, the pressure losses occurring during droplet formation, and a spherical droplet geometrical function. Two numerical resolution methods are implemented and compared. For this model, three parameters have to be identified from the experimental data. The identification procedure is explained in the paper and the comparison with experimental results shows the ability of the present model to reproduce the eruptive nature of liquid water breakthrough from the GDL. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.