The clogging or jamming of non-Brownian particle suspensions is a ubiquitous problem hindering the efficiency of particle-liquid and particle-particle separations. Motivated by pressure screening in the Pulp and Paper Industry, we characterize jamming of dilute and semi-dilute mono-disperse rigid-rod suspension passing through channels mimicking dead-end and cross-flow filtration membranes, experimentally, using particle-tracking velocimetry. We observe that jams nucleated by either bridging of isolated particles across the constriction or by localized mechanical entanglement of the particles, i.e. flocculation. Uniquely, we observe floc-formation during acceleration into the aperture and report this as the primary mechanism for jam-ming events. We characterized the accumulation-release cycles of the jamming event using an exponential probability distribution (Ψ); this distribution is indicative of a Poisson process. For jams nucleated by single-particle bridging, Ψ is (primarily) related to the number of fibres passing through the aperture; this is similar to dry, granular materials. For floc-based nucleation events, Ψ is (primarily) related to the suspension concentration with the average time between jams decreasing inversely with the square root of the initial suspension concentration. For the conditions tested, the distribution of Ψ was insensitive to changes in constriction geometry.