diff --git a/src/render/draw_hillshade.js b/src/render/draw_hillshade.js
index f9d7a1577e8..bcaefbafa89 100644
--- a/src/render/draw_hillshade.js
+++ b/src/render/draw_hillshade.js
@@ -116,13 +116,23 @@ function prepareHillshade(painter, tile) {
 
         gl.activeTexture(gl.TEXTURE1);
 
+        // if UNPACK_PREMULTIPLY_ALPHA_WEBGL is set to true prior to drawHillshade being called
+        // tiles will appear blank, because as you can see above the alpha value for these textures
+        // is always 0
+        gl.pixelStorei(gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, (false: any));
+
+
+        tile.demTexture = tile.demTexture || painter.getTileTexture(tile.tileSize);
         if (tile.demTexture) {
             tile.demTexture.update(pixelData[0], false);
+            // for some reason flow thinks tile.demTexture can be null or undefined here :sob:
+            (tile.demTexture: any).bind(gl.NEAREST, gl.CLAMP_TO_EDGE);
         } else {
             tile.demTexture = new Texture(gl, pixelData[0], gl.RGBA, false);
+            tile.demTexture.bind(gl.NEAREST, gl.CLAMP_TO_EDGE);
         }
 
-        (tile.demTexture: any).bind(gl.NEAREST, gl.CLAMP_TO_EDGE);
+
         gl.activeTexture(gl.TEXTURE0);
 
         if (!tile.texture) {
@@ -131,7 +141,6 @@ function prepareHillshade(painter, tile) {
             tile.texture.clear(TERRAIN_TILE_HEIGHT, TERRAIN_TILE_WIDTH);
         }
 
-        gl.pixelStorei(gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, (false: any));
         gl.viewport(0, 0, TERRAIN_TILE_WIDTH, TERRAIN_TILE_HEIGHT);
 
 
diff --git a/src/source/raster_dem_tile_source.js b/src/source/raster_dem_tile_source.js
index 5d94ddcf5f9..a3c8158eb5f 100644
--- a/src/source/raster_dem_tile_source.js
+++ b/src/source/raster_dem_tile_source.js
@@ -121,7 +121,11 @@ class RasterDEMTileSource extends RasterTileSource implements Source {
 
 
     unloadTile(tile: Tile) {
-        tile.unloadDEMData();
+        if (tile.demTexture) this.map.painter.saveTileTexture(tile.demTexture);
+        if (tile.dem) delete tile.dem;
+        delete tile.neighboringTiles;
+
+        tile.state = 'unloaded';
         this.dispatcher.send('removeDEMTile', { uid: tile.uid, source: this.id }, undefined, tile.workerID);
     }
 
diff --git a/src/source/tile.js b/src/source/tile.js
index 1601068a0a3..d7752024c26 100644
--- a/src/source/tile.js
+++ b/src/source/tile.js
@@ -226,12 +226,6 @@ class Tile {
         this.state = 'unloaded';
     }
 
-    unloadDEMData() {
-        this.dem = null;
-        this.neighboringTiles = null;
-        this.state = 'unloaded';
-    }
-
     redoPlacement(source: any) {
         if (source.type !== 'vector' && source.type !== 'geojson') {
             return;