diff --git a/buildbucket/buildbucket_environment.yaml b/buildbucket/buildbucket_environment.yaml
index 13e442b0f896f66f6e4038055df1fc037c0e74a9..6dc4e56a92f049edb6f52df51414f0efb9c9f621 100644
--- a/buildbucket/buildbucket_environment.yaml
+++ b/buildbucket/buildbucket_environment.yaml
@@ -4,7 +4,7 @@ channels:
 dependencies:
   - conda-pack
   - curl
-  - dask
+  - dask<=2.3.0 # this is to avoid dask hangs we saw using 2021.2.0
   - distributed
   - netcdf4
   - pip