The catastrophic fault pattern is a pattern of faults occurring at strategic locations that may render a system unusable regardless of its component redundancy and of its reconfiguration capabilities. In this paper, we extend the characterization of catastrophic fault patterns known for linear arrays to two-dimensional VLSI arrays in which all links are unidirectional. We determine the minimum number of faults required for a fault pattern to be catastrophic and give algorithm for the construction of catastrophic fault patterns with minimum number of faults.