diff --git a/CHANGES.rst b/CHANGES.rst
index 67ec1c0ff..10ef59099 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,7 +4,7 @@ Changelog
 
 v0.47.0 (unreleased)
 --------------------
-Contributors to this version: Juliette Lavoie (:user:`juliettelavoie`), Pascal Bourgault (:user:`aulemahal`), Trevor James Smith (:user:`Zeitsperre`), David Huard (:user:`huard`).
+Contributors to this version: Juliette Lavoie (:user:`juliettelavoie`), Pascal Bourgault (:user:`aulemahal`), Trevor James Smith (:user:`Zeitsperre`), David Huard (:user:`huard`), Éric Dupuis (:user:`coxipi`).
 
 Announcements
 ^^^^^^^^^^^^^
@@ -20,7 +20,7 @@ Bug fixes
 ^^^^^^^^^
 * Fixed a bug with ``n_escore=-1`` in ``xclim.sdba.adjustment.NpdfTransform``. (:issue:`1515`, :pull:`1515`).
 * In the documentation, fix the tooltips in the indicator search results. (:issue:`1524`, :pull:`1527`).
-* If chunked inputs are passed to indicators ``mean_radiant_temperature``  and ``potential_evapotranspiration``, sub-calculations of the solar angle will also use the same chunks, instead of a single one of the same size as the data. (:issue:`1536`, :pull:`1542`).
+* If chunked inputs are passed to indicators ``mean_radiant_temperature`` and ``potential_evapotranspiration``, sub-calculations of the solar angle will also use the same chunks, instead of a single one of the same size as the data. (:issue:`1536`, :pull:`1542`).
 
 Internal changes
 ^^^^^^^^^^^^^^^^
@@ -28,6 +28,7 @@ Internal changes
 * `pip check` in conda builds in GitHub workflows have been temporarily set to always pass. (:pull:`1531`).
 * Configure RtD search rankings to emphasize notebooks and indicators over indices and raw source code. (:pull:`1526`).
 * Addressed around 100 very basic `mypy` typing errors and call signature errors. (:pull:`1532`).
+* Use the intermediate step ``_cumsum_reset_on_zero`` instead of ``rle`` which is sufficient in ``_boundary_run``. (:issue:`1405`, :pull:`1530`).
 
 v0.46.0 (2023-10-24)
 --------------------
diff --git a/xclim/indices/run_length.py b/xclim/indices/run_length.py
index 3ca9607a0..855f4e4c3 100644
--- a/xclim/indices/run_length.py
+++ b/xclim/indices/run_length.py
@@ -416,7 +416,7 @@ def _boundary_run(
     ufunc_1dim: str | bool,
     position: str,
 ) -> xr.DataArray:
-    """Return the index of the first item of the first run of at least a given length.
+    """Return the index of the first item of the first or last run of at least a given length.
 
     Parameters
     ----------
@@ -493,9 +493,10 @@ def find_boundary_run(runs, position):
         out = coord_transform(out, da)
 
     else:
-        # for "first" run, return "first" element in the run (and conversely for "last" run)
-        d = rle(da, dim=dim, index=position)
+        # _cusum_reset_on_zero() is an intermediate step in rle, which is sufficient here
+        d = _cumsum_reset_on_zero(da, dim=dim, index=position)
         d = xr.where(d >= window, 1, 0)
+        # for "first" run, return "first" element in the run (and conversely for "last" run)
         if freq is not None:
             out = d.resample({dim: freq}).map(find_boundary_run, position=position)
         else: