Wildland fire conditions continue to be near “Critical” over much of the state, but is pronounced in western Oklahoma, the Panhandle and counties NW of Interstate 44. All fuel classes continue to dry down including heavy fuels which have reached single-digit moisture values. This equates to very rapid rates of spread, extended flame lengths, increased Probability of Ignition (PIG), complete fuel consumption and the potential for long-range spotting.
A Red Flag Warning will be in place from 12:00 noon through 8:00 p.m. for fifteen (15) western Oklahoma counties. Please refer to http://www.weather.gov/ for the latest updates to the fire weather forecast.
MONDAY: “Near Critical” to “Critical” fire weather is expected to develop by early afternoon. Anticipate good overnight humidity recovery in fine fuels, but this will rapidly erode with dry air pushing into the area. A cold front will follow a surface low pressure system eastward. Winds are expected to shift to north/northwest with the passage of the front. The forecast for sustained winds 15-20 mph with gusts near 30 mph will result in extreme rates of fire spread. Dormant grass fuel moisture will potentially fall into the 3-4% range which translates into very rapid rates of spread and significant fireline intensity (heat output).
Potential Fire Behavior Head Fire Parameters (rate of spread (ROS) and flame lengths (FL):
Short Grass / Pasture: maximum ROS 50-150 ft./min., FL 7-11 ft.
Tall Grass / Prairie: maximum ROS 100-300 ft./min., FL 14-25 ft.
- Grass/Shrub/Redcedar: maximum ROS 50-150 ft./min., FL 9-15 ft.
Expect single and group tree torching in the cedar, a Probability of Ignition of 75-90% and a spotting potential of .7-1.5 miles. Predicted fire behavior and the potential over the next 36-hours indicates that frontal assaults should be avoided. Do not engage in frontal assault tactics. Make sure to anchor the fire to a road, creek or to the cold black and the have resources flank the fire using direct attack. If possible, work the fire from inside the black. Avoid putting resources in unburned fuels. When protecting structures ensure that you have identified at least two (2) escape routes and make sure everyone knows where their safety zone is located. Establish “trigger points” for re-evaluating tactics. Remember the PACE acronym. Have a Primary, an Alternate, a Contingency and an Emergency plan in place. Make sure that “Leaders Intent” is clear, concise and understood.
Tuesday and Wednesday may provide some brief relief from current conditions, but elevated fire weather conditions are forecast to return on Thursday. 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 - including Engine Tactics and Wildland/Urban Interface Tactics - for review at http://www.forestry.ok.gov/tailgate.
Be Alert, Keep Calm, Think Clearly, Act Decisively
Standard Firefighting Orders
1. Keep informed on fire weather conditions and forecasts.
2. Know what your fire is doing at all times.
3. Base all actions on current and expected behavior of the fire.
4. Identify escape routes and safety zones and make them known.
5. Post lookouts when there is possible danger.
6. Be alert. Keep calm. Think clearly. Act decisively.
7. Maintain prompt communications with your forces, your supervisor, and adjoining forces.
8. Give clear instructions and insure they are understood.
9. Maintain control of your forces at all times.
10. Fight fire aggressively, having provided for safety first.
Four common denominators of fire behavior on tragedy fires:
1. On relatively small fires or deceptively quiet areas of large fires.
2. In relatively light fuels, such as grass, herbs, and light brush.
3. When there is an unexpected shift in wind direction or wind speed.
4. 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 Sun, March 19, 2017
by Communications filed under