diff --git a/src/relations.jl b/src/relations.jl
index e69ebef6..0c021a3a 100644
--- a/src/relations.jl
+++ b/src/relations.jl
@@ -2796,7 +2796,7 @@ and, optionally,
     q_vap = vapor_specific_humidity(q)
     p_vap = q_vap * air_density(param_set, T, p, q) * R_v * T
     p_vap_sat = saturation_vapor_pressure(param_set, phase_type, T)
-    return p_vap / p_vap_sat
+    return p_vap / (p_vap_sat + eps(FT(0)))
 end
 
 """