diff --git a/python/s2snow/snow_detector.py b/python/s2snow/snow_detector.py
index 12d4a66c65ad7ba996f217b69fb16c60df38073d..8acc29c16cbd69e916e62692d5ca871f3bb9d4ea 100644
--- a/python/s2snow/snow_detector.py
+++ b/python/s2snow/snow_detector.py
@@ -247,7 +247,7 @@ class snow_detector:
         self.rRed_pass2 *= self.multi
         self.fsnow_lim = snow.get("fsnow_lim")
         self.fsnow_total_lim = snow.get("fsnow_total_lim")
-        self.zs = -1  # default value when zs is not set
+        self.zs = -1000  # default value when zs is not set
 
         # Define the minimum amount of clear pixels altitude bin
         self.fclear_lim = snow.get("fclear_lim", 0.1)