In this paper we investigate automated methods for externalizing internal memory data structures.We consider a class of balanced trees that we call weight-balanced partitioning trees (or wp-trees) for indexing a set of points in RdWell-known examples of wp-trees include kdtrees, BBD-trees, pseudo-quad-trees, and BAR-trees. Given an efficient external wp-tree construction algorithm, we present a general framework for automatically obtaining a dynamic external data structure. Using this framework together with a new general construction (bulk loading) technique of independent interest, we obtain data structures with guaranteed good update performance in terms of I/O transfers. Our approach gives considerably improved construction and update I/O bounds for e.g. external kd-trees and BBD-trees. © 2011 Springer-Verlag Berlin Heidelberg.