diff --git a/includes/powder.h b/includes/powder.h
index c888e6b91..cbab5a2e1 100644
--- a/includes/powder.h
+++ b/includes/powder.h
@@ -759,6 +759,7 @@ extern int portal_rx[8];
 extern int portal_ry[8];
 
 extern int wire_placed;
+extern int force_stacking_check;
 
 extern playerst player;
 extern playerst player2;
diff --git a/src/main.c b/src/main.c
index b181182d2..967df060c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1734,6 +1734,8 @@ int main(int argc, char *argv[])
 						bmap[cby][cbx] = cb_bmap[cby][cbx];
 						emap[cby][cbx] = cb_emap[cby][cbx];
 					}
+
+				force_stacking_check = 1;//check for excessive stacking of particles next time update_particles is run
 			}
 		}
 #ifdef INTERNAL
diff --git a/src/powder.c b/src/powder.c
index f7c2d9ba9..9fcb1f0bf 100644
--- a/src/powder.c
+++ b/src/powder.c
@@ -29,6 +29,7 @@
 int wire_placed = 0;
 
 int lighting_recreate = 0;
+int force_stacking_check = 0;//whether to force a check for excessively stacked particles
 
 playerst player;
 playerst player2;
@@ -1518,28 +1519,29 @@ void update_particles_i(pixel *vid, int start, int inc)
 	if (sys_pause&&!framerender)//do nothing if paused
 		return;
 		
-	//if ((rand()%NPART)<NUM_PARTS*2) // run more often when more particles are on screen (since this is often due to excessive stacking)
-	if (1)
+	if (force_stacking_check || (rand()%10)==0)
 	{
+		force_stacking_check = 0;
 		excessive_stacking_found = 0;
 		for (y=0; y<YRES; y++)
 		{
 			for (x=0; x<XRES; x++)
 			{
 				// Use a threshold, since some particle stacking can be normal (e.g. BIZR + FILT)
-				// Setting pmap_count[y][x] >= NPART means BHOL will form in that spot
+				// Setting pmap_count[y][x] > NPART means BHOL will form in that spot
 				if (pmap_count[y][x]>5)
 				{
 					if (bmap[y/CELL][x/CELL]==WL_EHOLE)
 					{
-						// Allow more stacking in E-hole, allow up to 1500 particles
+						// Allow more stacking in E-hole
 						if (pmap_count[y][x]>1500)
 						{
 							pmap_count[y][x] = pmap_count[y][x] + NPART;
 							excessive_stacking_found = 1;
 						}
 					}
-					else
+					// Random chance to turn into BHOL that increases with the amount of stacking, up to a threshold where it is certain to turn into BHOL
+					else if (pmap_count[y][x]>1500 || (rand()%1600)<=(pmap_count[y][x]+100))
 					{
 						pmap_count[y][x] = pmap_count[y][x] + NPART;
 						excessive_stacking_found = 1;
@@ -1564,7 +1566,7 @@ void update_particles_i(pixel *vid, int start, int inc)
 							{
 								create_part(i, x, y, PT_NBHL);
 								parts[i].temp = MAX_TEMP;
-								parts[i].tmp = pmap_count[y][x]-NPART;
+								parts[i].tmp = pmap_count[y][x]-NPART;//strength of grav field
 								pmap_count[y][x] = NPART;
 							}
 							else
diff --git a/src/save.c b/src/save.c
index 7e3c26bc7..9a1023581 100644
--- a/src/save.c
+++ b/src/save.c
@@ -54,6 +54,7 @@ int parse_save(void *save, int size, int replace, int x0, int y0, unsigned char
 	{
 		return 1;
 	}
+	force_stacking_check = 1;//check for excessive stacking of particles next time update_particles is run
 	if(saveData[0] == 'O' && saveData[1] == 'P' && saveData[2] == 'S')
 	{
 		return parse_save_OPS(save, size, replace, x0, y0, bmap, vx, vy, pv, fvx, fvy, signs, partsptr, pmap);