Ticker for December 16, 2010

                
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December 16, 2010  December 16, 2010  December 16, 2010  December 16, 2010


Guest Tickerification time seeing how the spreading dry conditions across the
state are causing some to see the fire season of 2005-06 all over again. Who
better to talk about drought, fire danger and burn bans (oh my!) than the
Oklahoma Mesonet's own resident fire-weather expert, Dr. J.D. Carlson. J.D.
makes no prediction concerning the severity of the rest of the fire season but
does provide some very important information that can increase our understanding
of fire danger.

Take it away J.D.


Gary McManus
Associate State Climatologist
Oklahoma Climatological Survey
(405) 325-2253
gmcmanus@mesonet.org

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Drought, Fire Danger, and Burn Bans

by Dr. J. D. Carlson, Fire Meteorologist, OSU, Stillwater

In the 2008 Oklahoma legislative session, a law was passed that allows county
commissioners to enact and rescind burn bans in their county.  Prior to this,
only the Governor after consultation with Oklahoma Forestry Services could
enact and rescind burn bans.  County burn bans last 30 days at a time, but can
be canceled earlier if conditions warrant.

There are four criteria, all of which must be met, before a county can even
consider putting on a burn ban:

1) Moderate, severe, or extreme drought conditions exist within the county as
defined by the weekly US Drought Monitor

2) No more than a half of an inch of precipitation is forecast by the National
Weather Service for the next three days

3) Fire occurrence is significantly greater than normal for the season and/or
initial attack on a significant number of wildland fires has been unsuccessful
due to extreme fire behavior

and

4) More than 20% of the wildfires in the county have been caused by escaped
debris burning or controlled burning activities

OK-FIRE, a program of the Oklahoma Mesonet, provides links to determine whether
the first two criteria are met.

http://okfire.mesonet.org

With respect to the first criterion, go to the FIRE section and you?ll see an
item entitled ?County Burn Bans? in the left menu area. In that section you
will find a link to the latest Oklahoma drought map (based on the US Drought
Monitor).  In addition there are links to a map of current county burn bans
within Oklahoma, the latest national drought map, and a summary of the burn ban
legislation.

With respect to the second criterion, go to the WEATHER section, then Forecasts,
then National Weather Service (NWS).  In that section you will see a list of
the four offices (Amarillo, Norman, Tulsa, and Shreveport) that cover portions
of Oklahoma.  Click on the office that covers your county and you will be taken
to the home page of that NWS office.  Click on your county and a page will come
up giving a text forecast for the next seven days.  If you scroll down to the
very bottom of that page, on the right-hand side you will see a product
entitled ?Hourly Weather Graph?.  Click on that link and you will be taken to a
page having a number of forecast graphs, one of which is for ?Rain?.  If any
significant rain (or snow/sleet/ice) is forecast, the amounts will shown
(liquid equivalent) in the Rain graph.

As fire meteorologist and director of the OK-FIRE program, I am aware of a
number of misunderstandings within the general public about the relationship of
drought to fire danger.  While drought is a factor in fire danger, it is
certainly not the most important factor.  The major factors are the greenness
of the fuels and the hour-to-hour weather conditions.  With respect to weather,
the primary drivers for fire danger are low relative humidity (#1 factor) and
high wind speeds (#2 factor).  One can have low fire danger during a drought if
the relative humidity is sufficiently high and the wind speeds are sufficiently
low.  During such conditions, prescribed burns can occur with minimal risk.  On
the other hand, one can have high fire danger without a drought if the relative
humidity is sufficiently low and the wind speeds are sufficiently high.
Programs like OK-FIRE provide a scientific basis to predicting fire danger, as
the fire model used integrates not only drought conditions, but the more
important fuel greenness levels and, above all, the hour-to-hour weather
conditions.  For questions about fire danger or to learn more about the OK-FIRE
program, feel free to contact me at jdc@okstate.edu.