diff --git a/src/ol/interaction/modifyinteraction.js b/src/ol/interaction/modifyinteraction.js
index 787905ef2a..75979b419e 100644
--- a/src/ol/interaction/modifyinteraction.js
+++ b/src/ol/interaction/modifyinteraction.js
@@ -94,7 +94,7 @@ ol.interaction.Modify = function(options) {
    * @type {boolean}
    * @private
    */
-  this.snappedToVertex_;
+  this.snappedToVertex_ = false;
 
   /**
    * @type {Array}