From ba5cd68fbb5a5be98e196b51aecda2f4bbb7f7a9 Mon Sep 17 00:00:00 2001
From: Matthew Masarik <86749872+MatthewMasarik-NOAA@users.noreply.github.com>
Date: Mon, 5 Feb 2024 13:45:25 -0500
Subject: [PATCH] w3fld1md.F90: fix divide by zero in CRIT2 parameter (#1184)

---
 model/src/w3fld1md.F90 | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/model/src/w3fld1md.F90 b/model/src/w3fld1md.F90
index 960fd185a..10b2fce08 100644
--- a/model/src/w3fld1md.F90
+++ b/model/src/w3fld1md.F90
@@ -550,9 +550,13 @@ SUBROUTINE W3FLD1( ASPC, FPI, WNDX,WNDY, ZWND,               &
           TAUDIR=atan2(TAUY, TAUX)
           ! Note: add another criterion (stress direction) for iteration.
           CRIT1=(ABS(USTAR-USTRB)*100.0)/((USTAR+USTRB)*0.5) .GT. 0.1
-          CRIT2=(ABS(TAUDIR-TAUDIRB)*100.0/(TAUDIR+TAUDIRB)*0.5) .GT. 0.1
+          IF ((TAUDIR+TAUDIRB).NE.0.) THEN
+              CRIT2=(ABS(TAUDIR-TAUDIRB)*100.0/(TAUDIR+TAUDIRB)*0.5) .GT. 0.1
+          ELSE
+              CRIT2=.TRUE.
+          ENDIF
           IF (CRIT1 .OR. CRIT2) THEN
-            !            IF ((ABS(USTAR-USTRB)*100.0)/((USTAR+USTRB)*0.5) .GT. 0.1) THEN
+            !    IF ((ABS(USTAR-USTRB)*100.0)/((USTAR+USTRB)*0.5) .GT. 0.1) THEN
             USTRB=USTAR
             TAUDIRB=TAUDIR
             CTR=CTR+1