diff --git a/src/lbm/geometry/IntersectionRatio.impl.h b/src/lbm/geometry/IntersectionRatio.impl.h
index 95d7a8cbe241e96e70e4aa7c635462ea469f379e..fd19725e16de01230fb7148e8f1e51771e3b5943 100644
--- a/src/lbm/geometry/IntersectionRatio.impl.h
+++ b/src/lbm/geometry/IntersectionRatio.impl.h
@@ -30,8 +30,8 @@ real_t intersectionRatioBisection( const Body & body,
                                    const Vector3<real_t> & direction,
                                    const real_t epsilon )
 {
-   WALBERLA_ASSERT( !geometry::contains( body, fluidPoint ) );
-   WALBERLA_ASSERT(  geometry::contains( body, fluidPoint + direction ) );
+   WALBERLA_ASSERT( !geometry::contains( body, fluidPoint ), "fluid point: " << fluidPoint );
+   WALBERLA_ASSERT(  geometry::contains( body, fluidPoint + direction ), "fluidPoint + direction: " << fluidPoint + direction );
    
    const real_t sqEpsilon         = epsilon * epsilon;
    const real_t sqDirectionLength = direction.sqrLength();