diff --git a/dbt-snowflake/.changes/unreleased/Dependencies-20251010-095457.yaml b/dbt-snowflake/.changes/unreleased/Dependencies-20251010-095457.yaml
new file mode 100644
index 000000000..2ef19bfe0
--- /dev/null
+++ b/dbt-snowflake/.changes/unreleased/Dependencies-20251010-095457.yaml
@@ -0,0 +1,6 @@
+kind: Dependencies
+body: Upgrade snowflake-connector-python to 4.0.0
+time: 2025-10-10T09:54:57.268488-05:00
+custom:
+    Author: wiggzz
+    PR: "1368"
diff --git a/dbt-snowflake/.changes/unreleased/Fixes-20251003-140016.yaml b/dbt-snowflake/.changes/unreleased/Fixes-20251003-140016.yaml
new file mode 100644
index 000000000..a26807230
--- /dev/null
+++ b/dbt-snowflake/.changes/unreleased/Fixes-20251003-140016.yaml
@@ -0,0 +1,6 @@
+kind: Fixes
+body: Set client prefetch threads to 1 to prevent deadlock at exit
+time: 2025-10-03T14:00:16.074315-05:00
+custom:
+    Author: wiggzz
+    Issue: "1368"
diff --git a/dbt-snowflake/pyproject.toml b/dbt-snowflake/pyproject.toml
index 572b78f35..bebfccad9 100644
--- a/dbt-snowflake/pyproject.toml
+++ b/dbt-snowflake/pyproject.toml
@@ -26,7 +26,7 @@ dependencies = [
     "dbt-common>=1.10,<2.0",
     "dbt-adapters>=1.16.6,<2.0",
     # lower bound pin due to CVE-2025-24794
-    "snowflake-connector-python[secure-local-storage]>=3.13.1,<4.0.0",
+    "snowflake-connector-python[secure-local-storage]>=4.0.0,<5.0.0",
     "certifi<2025.4.26",
     # add dbt-core to ensure backwards compatibility of installation, this is not a functional dependency
     "dbt-core>=1.10.0rc0",
diff --git a/dbt-snowflake/src/dbt/adapters/snowflake/connections.py b/dbt-snowflake/src/dbt/adapters/snowflake/connections.py
index b83032a76..a1c173ea4 100644
--- a/dbt-snowflake/src/dbt/adapters/snowflake/connections.py
+++ b/dbt-snowflake/src/dbt/adapters/snowflake/connections.py
@@ -394,6 +394,7 @@ def connect():
                     application="dbt",
                     insecure_mode=creds.insecure_mode,
                     session_parameters=session_parameters,
+                    ocsp_root_certs_dict_lock_timeout=10,  # cert lock can cause deadlock without timeout, see https://github.com/snowflakedb/snowflake-connector-python/issues/2213
                     **creds.auth_args(),
                 )
 
diff --git a/dbt-snowflake/tests/unit/test_snowflake_adapter.py b/dbt-snowflake/tests/unit/test_snowflake_adapter.py
index 3a7cac5be..c3d83df4f 100644
--- a/dbt-snowflake/tests/unit/test_snowflake_adapter.py
+++ b/dbt-snowflake/tests/unit/test_snowflake_adapter.py
@@ -292,6 +292,7 @@ def test_client_session_keep_alive_false_by_default(self):
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 ),
             ]
         )
@@ -325,6 +326,7 @@ def test_client_session_keep_alive_true(self):
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=None,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -352,6 +354,7 @@ def test_client_has_query_tag(self):
                     application="dbt",
                     insecure_mode=False,
                     session_parameters={"QUERY_TAG": "test_query_tag"},
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -387,6 +390,7 @@ def test_user_pass_authentication(self):
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -421,6 +425,7 @@ def test_authenticator_user_pass_authentication(self):
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -451,6 +456,7 @@ def test_authenticator_externalbrowser_authentication(self):
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -485,6 +491,7 @@ def test_authenticator_oauth_authentication(self):
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -519,6 +526,7 @@ def test_authenticator_private_key_authentication(self, mock_get_private_key):
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -553,6 +561,7 @@ def test_authenticator_private_key_authentication_no_passphrase(self, mock_get_p
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -585,6 +594,7 @@ def test_authenticator_jwt_authentication(self):
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -615,6 +625,7 @@ def test_query_tag(self):
                     insecure_mode=False,
                     session_parameters={"QUERY_TAG": "test_query_tag"},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -644,6 +655,7 @@ def test_reuse_connections_with_keep_alive(self):
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -678,6 +690,7 @@ def test_authenticator_private_key_string_authentication(self, mock_get_private_
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )
@@ -714,6 +727,7 @@ def test_authenticator_private_key_string_authentication_no_passphrase(
                     insecure_mode=False,
                     session_parameters={},
                     reuse_connections=True,
+                    ocsp_root_certs_dict_lock_timeout=10,
                 )
             ]
         )