diff --git a/src/ICE/icethd_pnd.F90 b/src/ICE/icethd_pnd.F90
index 825c4345958e148800c614794f1797be3830f233..f268859aea547cb7ea0752dba75e1f99bf6ce349 100644
--- a/src/ICE/icethd_pnd.F90
+++ b/src/ICE/icethd_pnd.F90
@@ -686,8 +686,8 @@ CONTAINS
                         ! differential growth of base of surface floating ice layer
                         zdTice = MAX( - ( t_su(ji,jj,jl) - zTd ) , 0._wp ) ! > 0
                         zomega = rcnd_i * zdTice / zrhoi_L
-                        zdHui  = SQRT( 2._wp * zomega * rDt_ice + ( v_il(ji,jj,jl) / a_i(ji,jj,jl) )**2 ) &
-                               - v_il(ji,jj,jl) / a_i(ji,jj,jl)
+                        zdHui  = SQRT( 2._wp * zomega * rDt_ice + ( v_il(ji,jj,jl) / a_ip(ji,jj,jl) )**2 ) &
+                               - v_il(ji,jj,jl) / a_ip(ji,jj,jl)
                         zdvice = min( zdHui*a_ip(ji,jj,jl) , v_ip(ji,jj,jl) )
 
                         IF ( zdvice > epsi10 ) THEN