Landslide and
Debris Flows
Modified by the Office of Preparedness
with special thanks to FEMA, CERT, and Citizen Corps
A Landslide Is…
• A rapid shift in land mass
– Typically associated with
periods of heavy rainfall
or rapid snowmelt
– Tends to worsen effects
of flooding that often
accompanies
landslides
L-1
Areas Prone to Landslides
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•
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Existing old landslides
Bases of steep slopes
Bases of drainage channels
Developed hillsides where leach-field
septic systems are used
L-2
Landslides in CO
• Like with severe weather, tornados, and
winter storms – there are landslide
advisories, watches, and warnings
• Pay attention to these, especially when
traveling on roadways through the
mountains
L-3
A Debris Flow Is…
• Essentially a river of solid
materials carried along by
water by flash floods or
heavy snow melt
• A debris flow can move
as fast as an avalanche
and go for miles from the
initiation point before
stopping
The aftermath of a debris flow following the High Park fire
2012
L-4
Debris Flows in CO
• In CO we most often see debris flows
following floods in burn scar areas
• The eroded soil cannot absorb water and it
collects at the top, once it becomes
saturated the land will give way along with
whatever is on top of it
L-5
During a Landslide or Debris Flow
• Stay aware of your environment
– Listen for sounds that could indicate moving
trees or rocks
– Avoid river valleys and low-lying areas
– Notice change in water levels and muddiness
– Do not cross a bridge if you see a debris flow
approaching it
– If you cannot escape a landslide or debris
flow, curl into a solid ball and cover your head
as best you can
L-6
After a Landslide or Debris Flow
• Check for people who may be injured or
trapped but do not enter the landslide/debris
flow area
 Direct responders to their locations when they
arrive
• Check for downed power lines and report
them to the utility companies
• Begin replanting to avoid further erosion and
land slides
L-7