diff --git a/qgis2fds_export_algo.py b/qgis2fds_export_algo.py
index 2b97dea..eaeebcb 100644
--- a/qgis2fds_export_algo.py
+++ b/qgis2fds_export_algo.py
@@ -268,6 +268,21 @@ def processAlgorithm(self, parameters, context, model_feedback):
                 extent_crs=utm_crs,
             )
 
+        # Check DEM layer is local, otherwise save it
+
+        dem_layer = DEMLayerParam.get_local(
+            algo=self,
+            parameters=parameters,
+            context=context,
+            feedback=feedback,
+            project=project,
+            extent=_transform_extent(
+                extent=utm_idem_extent, source_crs=utm_crs, dest_crs=dem_layer.crs()
+            ),  # FIXME not useful here
+        )
+
+        return {}  # FIXME
+
         # Clip, reproject, and interpolate the DEM
 
         feedback.setProgressText("\nClip, reproject, and interpolate the DEM...")
@@ -302,8 +317,6 @@ def processAlgorithm(self, parameters, context, model_feedback):
         if feedback.isCanceled():
             return {}
 
-
-
         # Sample Z values from interpolated DEM raster layer
 
         feedback.setProgressText(
@@ -617,4 +630,3 @@ def _load_fire_layer_bc(
                 if fire_geom.contains(g):
                     if bc != NULL:
                         sampling_layer.changeAttributeValue(f.id(), output_bc_idx, bc)
-
diff --git a/qgis2fds_params.py b/qgis2fds_params.py
index f1251bf..140d220 100644
--- a/qgis2fds_params.py
+++ b/qgis2fds_params.py
@@ -20,6 +20,9 @@
     QgsProcessingParameterDefinition,
     QgsProcessingParameterBoolean,
     QgsPoint,
+    QgsRasterFileWriter,
+    QgsRasterPipe,
+    QgsRasterLayer,
 )
 import os
 
@@ -202,12 +205,6 @@ def set(cls, algo, config, project):
     @classmethod
     def get(cls, algo, parameters, context, feedback, project):
         value = algo.parameterAsRasterLayer(parameters, cls.label, context)
-        # Check local
-        url = value.source()
-        if not os.path.isfile(url):
-            raise QgsProcessingException(
-                f"DEM layer data is not saved locally, cannot proceed.\n{url}"
-            )
         # Check valid
         if not value.crs().isValid():
             raise QgsProcessingException(
@@ -217,6 +214,69 @@ def get(cls, algo, parameters, context, feedback, project):
         feedback.setProgressText(f"{cls.desc}: {value}")
         return value
 
+    @classmethod
+    def get_local(
+        cls,
+        algo,
+        parameters,
+        context,
+        feedback,
+        project,
+        extent,  # in layer crs!
+        relpath="./layers",
+    ):
+        layer = algo.parameterAsRasterLayer(parameters, cls.label, context)
+        url = layer.source()
+        if os.path.isfile(url):
+            return layer
+        # Make and check absolute path
+        project_path = project.absolutePath()
+        if not project_path:
+            raise QgsProcessingException(
+                "Save QGIS project to disk, cannot proceed."
+            )  # FIXME message
+        path = os.path.join(project_path, relpath)
+        # Create layers directory
+        # FIXME see https://stackoverflow.com/questions/273192/how-do-i-create-a-directory-and-any-missing-parent-directories
+        if not os.path.isdir(path):
+            feedback.setProgressText(f"Create directory {path}...")
+            os.makedirs(path, exist_ok=True)
+            if not os.path.isdir(path):
+                raise QgsProcessingException(
+                    f"Error creating directory {path}, cannot proceed."
+                )
+        # Save layer
+        # FIXME set style
+        filepath = os.path.join(path, f"{layer.name()}_saved.tif")
+        file_writer = QgsRasterFileWriter(filepath)
+        pipe = QgsRasterPipe()
+        provider = layer.dataProvider()
+        ok = pipe.set(provider.clone())
+        if not ok:
+            raise QgsProcessingException(
+                f"Error saving layer data (pipe, {ok}), cannot proceed.\n{url}"
+            )
+        feedback.setProgressText(f"pipe prepared. ok: {ok}, url: {url}, path: {path}")
+        nCols = round(extent.width() / layer.rasterUnitsPerPixelX())  # FIXME
+        nRows = round(extent.height() / layer.rasterUnitsPerPixelY())  # FIXME
+        # FIXME align extent with original grid
+        err = file_writer.writeRaster(
+            pipe=pipe, nCols=nCols, nRows=nRows, outputExtent=extent, crs=layer.crs()
+        )
+        if err:
+            raise QgsProcessingException(
+                f"Error saving layer data (write, {err}), cannot proceed.\n{url}"
+            )
+        feedback.setProgressText(f"tif saved. ok: {ok}, url: {url}, path: {filepath}")
+        new_layer = QgsRasterLayer(filepath, f"{layer.name()}_saved")  # FIXME var name
+        if not new_layer.isValid():
+            raise QgsProcessingException(
+                f"Error loading saved layer, cannot proceed.\n{url}"
+            )
+        project.addMapLayer(new_layer)
+        project.writeEntry("qgis2fds", cls.label, filepath)
+        return new_layer
+
 
 class LanduseLayerParam:
     label = "landuse_layer"