diff --git a/configure.ac b/configure.ac
index e40888d4b66adbdfbcbc0595e1729d4748540ee3..9edd0ec29d057499465c90c5fb2116356a91566a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -174,7 +174,8 @@ AC_ARG_ENABLE([dim-of-world],
 esac])
 
 ALBERTA_ENABLE_FLAG([fortran-blas],
-  [Use BLAS routines for some basic linear algebra stuff.],
+  [Use Fortran BLAS routines for some basic linear algebra stuff and use some
+  other Fortran modules (e.g. gpskca for matrix-profile reduction).],
   [disabled],
   [USE_F77_BLAS],
   [DEFINE SUBST COND])