diff --git a/src/crater/crater_critical_slope.f90 b/src/crater/crater_critical_slope.f90
new file mode 100644
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+++ b/src/crater/crater_critical_slope.f90
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+!  Project     : CTEM
+!  Language    : Fortran 2003
+!
+!  Description : Forms the maximum slope for the initial crater morphology
+!  
+!
+!  Input
+!    Arguments : 
+!
+!  Output
+!    Arguments :
+!           
+! 
+!  Notes       :  
+!
+!**********************************************************************************************************************************
+
+
+function crater_critical_slope(user,crater,iradsq) result(critical)
+   use module_globals
+   use module_util
+   use module_crater, EXCEPT_THIS_ONE => crater_form_exterior_func
+   implicit none
+
+  ! Arguments
+   type(usertype),intent(in) :: user
+   type(cratertype),intent(in) :: crater
+   integer(I4B),intent(in) :: iradsq
+   real(DP) :: critical
+
+   ! Internal variables
+
+   critical = CRITSLP
+
+end function crater_critical_slope
+