diff --git a/thermal_events/strike_line_descriptor.py b/thermal_events/strike_line_descriptor.py
index bc0ac33..bdedc8e 100644
--- a/thermal_events/strike_line_descriptor.py
+++ b/thermal_events/strike_line_descriptor.py
@@ -29,7 +29,9 @@ class StrikeLineDescriptor(Base):
 
     thermal_event_instance_id = Column(
         BigIntegerType,
-        ForeignKey("thermal_events_instances.id"),
+        ForeignKey(
+            "thermal_events_instances.id", onupdate="CASCADE", ondelete="CASCADE"
+        ),
         index=True,
         comment="The id of the thermal event instance described by the descriptor",
     )
@@ -56,6 +58,7 @@ class StrikeLineDescriptor(Base):
     instance = relationship(
         "ThermalEventInstance",
         lazy="subquery",
+        passive_deletes=True,
         back_populates="strike_line_descriptor",
     )
 
diff --git a/thermal_events/thermal_event_instance.py b/thermal_events/thermal_event_instance.py
index a75b8f5..83073ab 100644
--- a/thermal_events/thermal_event_instance.py
+++ b/thermal_events/thermal_event_instance.py
@@ -256,7 +256,9 @@ class ThermalEventInstance(Base):
     )
 
     strike_line_descriptor = relationship(
-        "StrikeLineDescriptor", back_populates="instance", cascade="all, delete-orphan"
+        "StrikeLineDescriptor",
+        back_populates="instance",
+        cascade="all, delete, delete-orphan",
     )
 
     _buffer = None  # image bugger used to draw polygons