diff --git a/src/topmodel.c b/src/topmodel.c
index a14291e..bab0e6c 100755
--- a/src/topmodel.c
+++ b/src/topmodel.c
@@ -148,6 +148,7 @@ extern void topmod(FILE *output_fptr, int nstep, int num_topodex_values,
 if(num_topodex_values > WARN_TOPODEX_INCREMENTS){
   printf("WARNING: num_topodex_values, %d, is greater than %d\n",
          num_topodex_values, WARN_TOPODEX_INCREMENTS);
+  exit(1);
 }
 double *ex = malloc(sizeof(double)*(num_topodex_values+1)); //+1 to maintin 1 based array indexing
 int ia,ib,in,irof,it,ir;