The month of March in Oklahoma is primetime for large and significant fire occurrence. Readily available-to-burn dormant fuels combining with critical fire weather results in many days of extreme fire danger. Today’s critical fire weather conditions resulting from a cold front approaching western Oklahoma were identified as early as one week ago by fire weather forecasters. Post-frontal fire weather on Tuesday and Wednesday will produce accelerated drying conditions with warm temperatures and very low relative humidity expanding well into eastern Oklahoma.
A Red Flag Warning/Fire Weather Watch is presently in place for areas in western Oklahoma and the Panhandle.
Please refer to http://www.weather.gov/ for the latest updates to the fire weather forecast.
MONDAY: Critical fire weather is expected to develop by early afternoon. Respectable overnight humidity recovery in fine fuels will rapidly erode with dry air pushing into the Warned area. The forecast for sustained southwest to west winds 25-30 mph with gusts near 40 mph will result in extreme rates of fire spread. Dormant grass fuel moisture will potentially fall into the 3-4% range which translates into significant fireline intensity.
Short Grass / Pasture: Maximum of 250-325 ft./min., head fire flame length 3-12 ft.
Tall Grass / Prairie: 300-500 ft./min. ( 5.7 mph), head fire flame length 15-30 ft.
Grass/Shrub/Redcedar: 150-250 ft./min, head fire flame length 12-24 ft.
Probability of Ignition will be near 80% in the afternoon hours meaning the potential for spotting will be high. The fuel moisture induced rate of combustion combined with the forecast winds may produce medium to long range spotting with one-quarter mile distances probable.
Potential fire behavior over the next few days dictates that frontal assault should be avoided – do not engage in frontal assault tactics. Anchor the fire at advantageous point (road, creek, cold black) and flank the fire if utilizing direct firefighting tactics. During direct attack, work the fire from the black to provide for quick escape to a safety zone. Avoid placing yourself in a situation where unburned fuel is between you and the fire. If protecting structures ensure that ingress and egress is identified, escape routes and safety zones are identified and equipment is pointed in a direction to facilitate rapid escape. Establish trigger points for re-evaluating tactics and develop contingency plans should the primary plan not be successful.
TUESDAY & WEDNESDAY: Much drier air will push across all of Oklahoma as dewpoint temperature plummets. Continued warm temperatures and the low dewpoints will result in relative humidity values ranging from 10% in the west to 19% in the east. Overnight moisture recovery in fine fuels is expected to be poor. Elevated burning conditions will continue overnight and facilitate a long, active burning period on Wednesday. Firefighters should expect increasing resistance to suppression efforts especially in timber where heavy fuels are available.
All firefighters are encouraged to review tactical operating procedures including engine tactics and fire operations in the wildland/urban interface. You can refer to the Oklahoma Wildland Tailgate Series for many topics for review at http://www.forestry.ok.gov/tailgate .
Specifically, you can reference an Engine Tactics review at: https://forestry.publishpath.com/Websites/forestry/images/Tailgate/Tailgate_Series_2_web_ready.pdf
Review Wildland/Urban Interface tactics by clicking the following link: https://forestry.publishpath.com/Websites/forestry/images/Tailgate/Tailgate_April_2015_FINAL.pdf
All firefighters are advised to take particular note of the 10 Standard Fire Orders with specific interest in the first three: (a complete list of the Standard Firefighting Orders below)
Keep informed on fire weather conditions and forecasts.
Know what your fire is doing at all times.
Base all actions on current and expected behavior of the fire.
Be Alert, Keep Calm, Think Clearly, Act Decisively
Standard Firefighting Orders
- Keep informed on fire weather conditions and forecasts.
- Know what your fire is doing at all times.
- Base all actions on current and expected behavior of the fire.
- Identify escape routes and safety zones and make them known.
- Post lookouts when there is possible danger.
- Be alert. Keep calm. Think clearly. Act decisively.
- Maintain prompt communications with your forces, your supervisor, and adjoining forces.
- Give clear instructions and insure they are understood.
- Maintain control of your forces at all times.
- Fight fire aggressively, having provided for safety first.
Four common denominators of fire behavior on tragedy fires:
- On relatively small fires or deceptively quiet areas of large fires.
- In relatively light fuels, such as grass, herbs, and light brush.
- When there is an unexpected shift in wind direction or wind speed.
- When fire responds to topographic conditions and runs uphill. Alignment of topography and wind during the burning period should always be considered a trigger point to re-evaluate strategy and tactics.
Posted on Mon, March 6, 2017