The GPM Ground Validation Environment Canada (EC) VAISALA Ceilometer GCPEx dataset was collected during the GPM Cold-season Precipitation Experiment (GCPEx) in Huronia, Canada from January 15, 2012 through March 1, 2012. The GPM Cold-season Precipitation Experiment (GCPEx) occurred in Ontario, Canada during the winter season of 2011-2012. GCPEx addressed shortcomings in the GPM snowfall retrieval algorithm by collecting microphysical properties, associated remote sensing observations, and coordinated model simulations of precipitating snow. The CT25K ceilometer uses pulsed diode laser LIDAR technology to derive backscatter profiles, cloud heights and vertical visibilities. It is also able to detect 3 cloud layers simultaneously.