LANDFIRE data is available to download from the LANDFIRE website as zipped ARCGIS files, which can be converted using GDAL to GeoTIFF files that are more easily read.
The following GDAL command can be used to translate the unzipped directories:
gdal_translate -co COMPRESS=LZW -ot Int16 -of GTiff path_to_adf_files landfire.tiffpath_to_adf_files should be a directory containing unzipped adf files and look something
like Slope\Grid\us_slp.