diff --git a/src/View/BoundaryCondition/Edit/Window.py b/src/View/BoundaryCondition/Edit/Window.py
index dba64da5d8a6d5340f770f89d6573f889aabe713..336a9671b4e7edfafcff4ca3cf70b7f541381b8a 100644
--- a/src/View/BoundaryCondition/Edit/Window.py
+++ b/src/View/BoundaryCondition/Edit/Window.py
@@ -224,8 +224,11 @@ class EditBoundaryConditionWindow(PamhyrWindow):
             self._d50sigma.sigmaChanged.connect(self.sigma_changed)
 
     def setup_dialog(self):
-        reach = self._data.reach(self._study.river)[0]
-        self.slope_value = abs(reach.get_incline_median_mean())
+        if len(self._data.reach(self._study.river)) > 0:
+            reach = self._data.reach(self._study.river)[0]
+            self.slope_value = abs(reach.get_incline_median_mean())
+        else:
+            self.slope_value = 0.0
 
     def d50_changed(self, value):
         self._undo_stack.push(