Energy Release Component
(ERC) Charts |
| By Individual Stations |
By Predictive Service Areas |
By Panel View - Arizona By Panel View - New Mexico |
|
AREA-WIDE |
ARIZONA |
NEW MEXICO |
SOUTHWEST AREA |
FUEL
MODEL "C" (Open Pine w/Grass (FM-2)) |
|||
FUEL
MODEL "G" (Closed, short-needle conifer (FM-10)) |
|||
FUEL
MODEL "K" (Light Slash (FM-11)) |
How are the Charts used?
All wildland protection agencies are directed to protect life, property,
and natural resources entrusted to them. These requirements dictate
strict attention be paid to the availability and use of suppression
resources. In the Southwest Area, the Charts are averaged over 3-day
periods. They
are primarily used to look at the seasonal trends, a comparison tool
against previous years, and as one tool used in determining the Area
preparedness level. Each chart displays the current year BI or ERC
values relative to the average for a 25-year period, the average of
the highest values during the same period, and when the values reach
the 90th and 97th percentiles. The Charts are not designed to be site
specific, they provide only a general picture of how conditions are
currently and how the season is progressing in the Southwest. Units
throughout the SWA produce their own local, site specific chart(s).
The Charts are only one of the components used in determining the SWA preparedness level. Other components that must be considered include; (1) current and long range forecasted weather affecting current and forecasted fire behavior/potential, (2) resource committments to incidents, (3) individual agency fire reports, (4) National Preparedness Level, (5) air quality considerations, and (6) fire suppression resource availability. The breakpoints in which the ERC Curve is used to assist in determining the area preparedness level are indicated by lines drawn horizontally (i.e. PL-2, PL-3, PL-4) on the chart. The 90th corresponds to the "very high" adjective reading and the 97th percentile corresponds to the "extreme" adjective reading.
How are the charts
generated?
There are 12 Automated
Weather Stations (AWS) strategically located throughout the National Forests
of the Southwest Area that collect data hourly throughout the year. Each
day around 1300 local time, this data is uploaded via satellite to the National
Weather Information System (WIMS) every hour. On Tuesday and Friday
of each week, the data is downloaded from WIMS and inserted into the FireFamily
Plus 4.0 software program, where the charts are derived.
The 12 stations are:
| 1. | AZ | Tusayan | 020207 | Kaibab NF |
| 2. | AZ | Flagstaff | 20209 | Coconino NF |
| 3. | AZ | Lakeside | 20303 | Apache-Sitgreaves NF's |
| 4. | AZ | Iron Springs | 20501 | Prescott NF |
| 5. | AZ | Globe | 20601 | Tonto NF |
| 6. | AZ | Saguaro | 20212 | Coronado NF |
| 7. | NM | Truchas | 290210 | Carson NF |
| 8. | NM | Jemez | 290702 | Santa Fe NF |
| 9. | NM | Grants | 291302 | Cibola NF |
| 10. | NM | Mountainair | 291501 | Cibola NF |
| 11. | NM | Beaverhead | 292001 | Gila NF |
| 12. | NM | Mayhill | 293002 | Lincoln NF |
What is the Burning
Index (BI)?
The Burning
Index (BI) is a number related to the contribution of fire behavior
to the effort of containing a fire. It is derived from the spread
and energy release components (Spread Component and Energy Release
Component). The rate of fire spread and the energy released in
the flaming zone, considered together, are the measns of rating
the difficulty of containment. The Bi is liinearly reated to the
length of flames at the head of the fire. It is calculated from
the SC and ERC using the relationships originally developed by
Byram for calculating flame length (Byram 1959).
What is the Energy Release
Component (ERC)?
The Energy Release
Component (ERC) is based on the estimated potential available energy
released per unit area in the flaming front of a fire. The day-to-day
variations of the ERC are caused by changes in the moisture contents of
the various fuel classes, including the 1,000 hour timelag class. The
ERC is derived from predictions of (1) the rate of heat release per
unit area during flaming combustion and (2) the duration of flaming.