Colloidal clogging is typically studied in pores with constrictions arranged in parallel or series.
In these systems, clogging statistics are governed by Poisson processes; the time interval between
clogging events exhibits an exponential distribution. However, an entirely different phenomenon
is observed in a gently tapered pore geometry. Unlike in non-tapered constrictions, rigid particles
clogging tapered microchannels form discrete and discontinuous clogs. In a parallelized system of
tapered microchannels, we analyze distributions of clog dimensions for different flow conditions. Clog
width distributions reveal a lognormal process, arising from concurrent clogging across independent
parallel microchannels. Clog lengths, however, which are analogous to growth time, are exponentially
distributed. This indicates a Poisson process where events do not occur simultaneously. These two
processes are contradictory: clogging events are statistically dependent within each channel while
clogs grow simultaneously across independent channels. The coexistence of Poisson and lognormal
processes suggests a transient Markov process in which clogs occur both independently of, and
dependently on, other clogs. Therefore, discussions of the stochastic character of clogging may
require holistic consideration of the quantities used to assess it. This study reveals small adjustments
to pore spaces can lead to qualitative differences in clogging dynamics, suggesting the importance
of geometry.