  We introduce and study a new directed sandpile model with threshold dynamics
and stochastic toppling rules. We show that particle conservation law and the
directed percolation-like local evolution of avalanches lead to the formation
of a spatial structure in the steady state, with the density developing a power
law tail away from the top. We determine the scaling exponents characterizing
the avalanche distributions in terms of the critical exponents of directed
percolation in all dimensions.
