Basic thread on today's fires and the the Incident Management Situation Report, commonly referred to as the Sit Report:

The report comes out each morning when fires are numerous & weekly when winter weather limits fires. 1/
https://www.nifc.gov/nicc/sitreprt.pdf

It's produced in Boise, ID by the National Interagency Fire Center's (NIFC) Predictive Services Intelligence Section, which is part of the National Interagency Coordination Center (NICC). 2/

Ideally, every significant fire that sends in a 209--Incident Status Summary--is included in the Sit Report. The NICC criteria for significant fires are those that exceed 300 acres in grass/brushy fuels, 100 acres in timber fuels, or have a Type 1 or 2 IMT assigned. 3/

If a non-wildfire incident (hurricane, flood, COVID response, etc.) has a significant number of wildland fire resources assigned, it too will appear on the Sit Report. 4/

Geographic areas, like the NW, Great Basin, NorCal, & the SW use 209s & other info to rank their fires in order of significance. This is often based on values at risk & complexity. Complexity is not just suppression, but can include logistics, socio-econ, & other factors. 5/

The regional reports are then gathered at NICC where they are ranked by significance & put in order on the Sit Report. NICC also uses the 209 info to make resource decisions on national resources like Hot Shots, kitchens, etc. 6/

When reading the report, the first region is considered the most significant and the first fire under each region is the most significant for that region. 7/

For example, today's top region is NorCal, which has the most activity due to recent lightning. The top fire is the #SCULightningComplex, which poses a big threat to communities & infrastructure. The last fire on the list is the July Complex, which is now 98% contained. 8/

Note: the first fire is not necessarily the most significant fire in the country, as multiple fires in one region may lead that region to be considered more significant than one major fire elsewhere--but it is not unusual for the most prominent fire to be in the top region. 9/

You'll also see a National Preparedness Level at the top. These range from 1-5 with 5 the highest level of fire activity & resource drain. The areas/regions also have a PL identified in their section. Here's the NIFC description of preparedness levels. 10/ https://www.nifc.gov/fireInfo/fireinfo_prepLevels.html

Those are the basics. Now for the arcane stuff. The top line on the Sit Report is "Initial Attack Activity," which is new starts reported the previous day. The categories break down like this:

Light: 0 – 199 fires
Moderate: 200 – 299 fires
Heavy: 300 fires and above
11/

If it is light or in the lower moderate range, there's a good chance initial attack resources were not overwhelmed. There may be a large fire or more depending on conditions and distribution of those starts, but usually no major national resource concerns. 12/

When you see a high moderate or a high, it usually means July 4th or lightning starting a bunch of fires in a region or state where conditions are favorable for fire. Initial attack resources can easily get overwhelmed & large fires are likely an outcome. 13/

If it's over 400, we're in real trouble. With a high number from a lightning bust, there's a good chance some starts were missed & so the following days may see elevated numbers as fires show themselves & are found. A high start day can influence numbers for a week or more. 14/

High start days also make it difficult to staff all fires, as new ones are reported constantly & priorities based on values at risk, complexities, & potential continually change. It's not uncommon for the last priority initial attack fire to eventually become a large one. 15/

According to this morning's National Sit Report, the initial attack activity was heavy yesterday with 332 new fires. However, 224 of them were in NorCal. The NW was the second-busiest region with 26 new fires. 16/

The NorCal number is large because of lightning starts over the last couple of days getting into the national system after a busy period by local dispatch or a fire finally getting big enough to be detected. The latter are called holdover or sleeper fires. 17/

With the lightning that popped over the NW & Northern Rockies during the last 24 hours, expect tomorrow's new fire number to be up considerably in both areas. 18/

Indeed, the NW Morning Brief shows 35 new fires this morning, up 9 from last night's submission that built today's National Sit Report. Those 9 and others identified today will show up in the Sit Report tomorrow. 19/

NorCal has 6 or 7 complexes on the report. A complex is two or more fires in the same area managed by one IMT or unified command. You often see complexes after a lightning storm. The IMT will prioritize the fires in their complex and allocate resources accordingly. 20/

On some complexes, fires will be treated separately while maintaining a larger view of resource use. In other situations, it may be advisable to treat different fires as one, particularly if there is a good chance they will merge at some point. 21/

Another line worth noting is "New Large Incidents," which is a good shorthand for both conditions and the resource impacts expected in the near term. On today's report, there are 332 new fires and 34 new large incidents. That's a high ratio & 19 of those are in NorCal. 22/

The number of Type 1 & 2 IMTs assigned today is 18. The number will be higher tomorrow--overnight, the NW assigned two IMTs to fires that are not on today's report. If an IMT is assigned, it typically means a long-duration fire that needs significant resources. 23/

If we start seeing 30 or more IMTs in the field, that's a sure sign national resources are stretched thin & difficult decisions about priorities are being made at every level. 24/

Since the Preparedness Level tops out at 5, one way firefighters have come up with to make sense of the scale of the situation is to look at the number of IMTs assigned. So, instead of PL5, we'll say it's PL-42 if 42 IMTS are working. 25/

The next couple of days will be tough with lightning in several states and gusty conditions in places that already have established fires. Folks across the West should plan for smoky skies and prepare to evacuate if needed. 26/

And yes, we all need to remember this is happening during a pandemic which not only affects firefighters, but evacs, LE, utility workers, and everyone else. Don't wait until the last minute--allow extra time for decision-making and action. Also, wear masks & keep distant. 27/

Finally, as the fires increase, understand that the decisions fire officials make are based on values at risk, complexity, & potential, not politics. We don't need politicians demanding resources for their constituents that will throw the entire national system out of whack. 28/

It's going to be a tough week and some of these fires will last for the remainder of the summer. Don't do things that will add to the burdens our firefighters face--they already face enough risk. Think ahead, plan, and take safe actions. Rain and snow will eventually come. 29/29