diff --git a/simgear/sky/cloud.cxx b/simgear/sky/cloud.cxx
index 4f9b5a15..b7f639a1 100644
--- a/simgear/sky/cloud.cxx
+++ b/simgear/sky/cloud.cxx
@@ -42,6 +42,7 @@ SGCloudLayer::SGCloudLayer( const string &tex_path )
     layer_transform(new ssgTransform),
     layer(0),
     texture_path(tex_path),
+    layer_span(0),
     layer_asl(0),
     layer_thickness(0),
     layer_transition(0),