Returning to Los Angeles from a hike this past weekend, we decided to take a detour to avoid some slow traffic on I-15. We turned off and headed south to I-40 along Harvard Road. It's a road I drive several times each year. There's a low section that crosses the (normally dry) Mojave River bed. That section can be flooded in winter (after storms) and in summer it can be covered in sand. Then we crested a rise in the road and were surprised to see the road partially covered with encroaching sand dunes.