  The finite coupling between Weyl nodes due to residual disorder is
investigated by magnetotransport studies in WTe$_2$. The anisotropic scattering
of quasiparticles is evidenced from classical and quantum transport
measurements. A new theoretical approach using a real band structure is
developed to calculate the dependence of the scattering anisotropy with the
correlation length of the disorder. A comparison between theory and experiments
reveals for the first time a short correlation length in WTe$_2$ ($\xi$~nm).
This result implies a significant coupling between Weyl nodes and other bands,
so that inter-node scattering strongly reduces topologically non-trivial
properties, such as the chiral anomaly.
