After months of devastating wildfires and waiting desperately for the upcoming wet winter season to bring relief, some communities in California are now at high risk of potentially deadly mudslides.

The fires burned thousands of square miles of land and left scorched and barren hillsides vulnerable to an especially dangerous fast-moving type of landslide that scientists call “debris flow.” Known less formally as mudslides, these flows are typically triggered by short, intense storms and can send tides of soil, ash, vegetation, rocks and even cars and homes careening downhill, destroying everything in their path.