  Granular flows through narrow outlets may be interrupted by the formation of
arches or vaults that clog the exit. These clogs may be destroyed by
vibrations. A feature which remains elusive is the broad distribution $p(\tau)$
of clog lifetimes $\tau$ measured under constant vibrations. Here, we propose a
simple model for arch-breaking, in which the vibrations are formally equivalent
to thermal fluctuations in a Langevin equation; the rupture of an arch
corresponds to the escape from an energy trap. We infer the distribution of
trap depths from experiments and, using this distribution, we show that the
model captures the empirically observed heavy tails in $p(\tau)$. These heavy
tails flatten at large $\tau$, consistently with experimental observations
under weak vibrations, but this flattening is found to be systematic, thus
questioning the ability of gentle vibrations to restore a finite outflow
forever. The trap model also replicates recent results on the effect of
increasing gravity on the statistics of clog formation in a static silo.
Therefore, the proposed framework points to a common physical underpinning to
the processes of clogging and unclogging, despite their different statistics.
