Today's topic during this flood safety and wildfire awareness week is flash floods.
Flash
floods are no strangers to Colorado. Close to 300 people have been
killed in flash floods across the centennial state since the year 1900.
The
worst flash flood occurred on July 31, 1976 in the Big Thompson Canyon
between Estes Park and Loveland. A nearly stationary storm produced
around 12 inches of rain in 4 hours and claimed 144 lives.
Two other notable flash floods in Colorado were:
The 1904 incident, just north of Pueblo that drowned just over 100 people as a bridge failed and plunged a train into Fountain Creek.
The 1997 Fort Collins episode killed five people and caused $200 million in property damage.
A
flash flood is defined as a rapid rise in water levels generally
occurring in less than 6 hours along large creeks normally dry
washes, arroyos or over normally dry land area and can occur with little
advanced notice.
Flash
floods frequently result from high rainfall rates and infrequently from
dam failures, levee failures or sudden breaks in river ice jams. Flash
floods are very destructive due to the force of the moving water and
the accompanying debris. This tremendous force can easily damage or
destroy roadways, bridges and buildings.
In
recent years, Colorado has seen major flooding and damage when heavy
rains have occurred on wildfire burn scar areas. If you are in or near a
burn scar area you need to plan ahead. Be aware of general flash flood
plans and procedures that have been developed and implemented by your
local emergency management officials. It’s up to you. You should know
your flash flood risks and make your plan to save your life and those
around you.
The
National Weather Service Forecast Offices will discuss flash flood
potential in daily hazardous weather outlooks and in graphical weather
stories on National Weather Service forecast office web sites.
During days when flash flooding is possible a flash flood watch will be issued.
During days when flash flooding is likely or occurring a flash flood warning will be issued.
When
a flash flood warning is issued for your area you need to act quickly
if you are in a drainage area or in other low spots. Know your escape
routes to higher ground and act as quickly as possible. It may be just a
short walk or climb to that higher ground.
Many
flash flood deaths occur in vehicles. Do not drive through a flooded
roadway. The water may be much deeper than you think because the roadway
may be damaged or washed away. One to two feet of water will carry away
most vehicles. Instead turn around don’t drown.
Flood safety and wildfire awareness week continues through this Saturday.
This article is provided by Colorado's National Weather Service.
