WFO Denver/Boulder

600 AM MDT SAT JUN 24 2006

     ...Lightning and Wildfires...

Colorado Lightning and Wildfire Preparedness Week concludes today, with
wildfires being the final topic.  During the past week we have presented
lightning information and safety rules.  Although wildfires are not an actual
weather phenomenon, wildfires are directly related to lightning and other
weather elements.

The wildfire threat in Colorado normally increases significantly after the
middle of June.  This threat usually peaks in early July and remains high
through August and early September.   Depending on climatic conditions, the
time of year for the peak wildfire threat can be about a month earlier or
later than normal.  Colorado averages about 2500 wildfires each year.

About half of all forest fires in Colorado are ignited by lightning. 
Additionally, many rangeland and wheatfield fires are caused by lightning.
Many of these lightning caused wildfires occur in the absence of rain.  When
this occurs, the lightning is commonly referred to as “dry lightning.”

Gusty winds often accompany thunderstorms which produce “dry lightning.” 
These gusty winds accelerate the spread of fires.  These thunderstorm winds
can quickly turn smoldering organic material into a raging fire.  Thunderstorm
winds tend to be erratic in direction and speed, posing one of the greatest
dangers for firefighters.

Lightning which strikes the ground is usually divided into two categories;
negative and positive strikes, depending on the ionic source region of the
thunderstorm.  The negative strikes are far more common than positive strikes. 
The positive strikes are more intense and have a longer duration than the
negative strikes and are more likely to ignite a fire.  Lightning detection
technology provides land managers, firefighters, and weather forecasters with
the ability to identify the general location and charge category of each
lightning strike within the continental United States.

National Weather Service forecasters help land managers and firefighters by
producing fire weather forecasts on a daily basis during the warm season. 
“Spot” fire weather forecasts are also provided for those who work on
prescribed burns or specific wildfires.  Forecasters also issue red flag
warnings for use by land managers when the combination of dry vegetation and
critical weather conditions will result in a high potential for the
development and spread of wildfires.  Land managers, in turn, typically inform
the general public of the fire danger in national parks, forests, and other
public lands.

During periods of extreme fire danger in forests and rangelands... should avoid being in areas where you might become trapped by a
wildfire. should avoid the use of matches or anything else which could ignite a

...make sure that hot parts of motorized equipment, such as mufflers, are not
allowed to come in contact with dry grasses or other potentially flammable

If you become trapped or cut-off by a wildfire, seek shelter in areas with
little or no fuel, such as rock slide areas or lakes.

For more information on wildfires and fire safety, please check out the
following web addresses:

Jim Pringle
Warning Coordination Meteorologist
WFO Grand Junction CO is the U.S. government's official web portal to all federal, state and local government web resources and services.