Debris flows are defined as moving masses of rock fragments, soil, water, and air with more than half of the particles consisting of sand-sized particles or larger. Flash floods and heavy rainfall can initiate debris flows especially in areas where wildfires have burned off vegetation that previously stabilized the slope.

Debris flows are dense - similar to landslides, however due to their water-sediment ratio and high pore-fluid pressures, debris flows behave and flow like water. In Nevada, these debris flows can flow out onto alluvial fans, through washes or arroyos, stream channels, and mountain gullies.

Debris flows are common in many locations throughout Nevada with some more notable occurrences taking place in southern Nevada in 2016 after heavy monsoonal downpours, and in Douglas County in 2014 and 2015 following thunderstorms and heavy rain in the area of Johnson Lane.

Floods along major streams and flash floods along normally dry washes are all too common phenomena in Nevada. NBMG research is helping to understand the frequency and severity of past floods. Efforts are underway in southern, northwestern, and north-central Nevada to determine the timing, magnitude, and frequency of these events.

Periodic flooding should be a major concern of property owners along Nevada's rivers and creeks and dry washes. The 1997 New Year's flood was a reminder of this for the people of northern Nevada, and the sporadic flash floods down the Las Vegas Wash are reminders for the people of southern Nevada. The numerous dry washes and arroyos across the state are commonly the sites of flash floods, especially during thunderstorms.