diff --git a/src/dump.cpp b/src/dump.cpp
index c648016abc..f50776f89d 100644
--- a/src/dump.cpp
+++ b/src/dump.cpp
@@ -94,6 +94,7 @@ Dump::Dump(LAMMPS *lmp, int /*narg*/, char **arg) :
 
   maxbuf = maxids = maxsort = maxproc = 0;
   maxsbuf = 0;
+  sortcol = 0;
 
   maxpbc = -1;