diff --git a/storage/local/instrumentation.go b/storage/local/instrumentation.go
index 91f9b72c1..85a7aa5e0 100644
--- a/storage/local/instrumentation.go
+++ b/storage/local/instrumentation.go
@@ -57,6 +57,7 @@ const (
 	unarchive          = "unarchive"
 	memoryPurge        = "purge_from_memory"
 	archivePurge       = "purge_from_archive"
+	requestedPurge     = "purge_on_request"
 	memoryMaintenance  = "maintenance_in_memory"
 	archiveMaintenance = "maintenance_in_archive"
 
diff --git a/storage/local/storage.go b/storage/local/storage.go
index 3ef755a30..9b1a4d644 100644
--- a/storage/local/storage.go
+++ b/storage/local/storage.go
@@ -527,6 +527,7 @@ func (s *memorySeriesStorage) DropMetricsForFingerprints(fps ...model.Fingerprin
 		}
 
 		s.fpLocker.Unlock(fp)
+		s.seriesOps.WithLabelValues(requestedPurge).Inc()
 	}
 }