diff --git a/Exec/DevTests/Bomex/Backtrace.0 b/Exec/DevTests/Bomex/Backtrace.0
new file mode 100644
index 000000000..ce39b6fb0
--- /dev/null
+++ b/Exec/DevTests/Bomex/Backtrace.0
@@ -0,0 +1,12 @@
+Host Name: LAPTOP-PO22H9R0
+=== If no file names and line numbers are shown below, one can run
+            addr2line -Cpfie my_exefile my_line_address
+    to convert `my_line_address` (e.g., 0x4a6b) into file name and line number.
+    Or one can use amrex/Tools/Backtrace/parse_bt.py.
+
+=== Please note that the line number reported by addr2line may not be accurate.
+    One can use
+            readelf -wl my_exefile | grep my_line_address'
+    to find out the offset for that line.
+
+ 0: ./ERF3d.gnu.TEST.MPI.ex(+
\ No newline at end of file
diff --git a/Source/Utils/Microphysics_Utils.H b/Source/Utils/Microphysics_Utils.H
index 1318221cd..eea6f095e 100644
--- a/Source/Utils/Microphysics_Utils.H
+++ b/Source/Utils/Microphysics_Utils.H
@@ -87,7 +87,7 @@ amrex::Real erf_esatw (amrex::Real t) {
     amrex::Real Tc = std::max(-80.0, t-273.16);
 
     amrex::Real esatw;
-    if (t>=273.15){
+    if (t<=273.15){
         esatw = (a0  + Tc*(a1 +Tc*(a2 +Tc*(a3 +Tc*(a4 +Tc*(a5 +Tc*(a6 +Tc*(a7 +a8 *Tc))))))))*100.;
     }else{
         esatw = (a0i + Tc*(a1i+Tc*(a2i+Tc*(a3i+Tc*(a4i+Tc*(a5i+Tc*(a6i+Tc*(a7i+a8i*Tc))))))))*100.;