Forest Service releases soil burn severity maps for some Montana wildfires

The U.S. Forest Service has just started releasing detailed soil burn severity maps for wildfires that burned in the Northern Rockies this year. Hopefully some of this information and these maps are shared by the news media and political leaders.

The Inciweb homepage is here.

Individual maps of some specific fires are here.

What’s the take home message from these soil burn severity maps? Looks like the 2017 wildfires burned in a mosaic pattern with lots of unburned, very low, and low to moderate soil burn severity.

SOME EXAMPLES FROM SPECIFIC WILDFIRES:

Only 3% of the acres burned in 45,000 acre Sapphire Complex Wildfires on Lolo National Forest had soil burn severity measured as “High.” Meanwhile, 78% of acres in Sapphire Complex Wildfires on the Lolo NF had soil burn severity measured as “Unburned” “Very Low” or “Low.”

The vast majority of the lightening-caused Park Creek fire was either unburned, or burned at low to moderate severity. Senator Daines, Rep Gianforte and the Montana timber industry – especially Ed Regan, resource manager for RY Timber – blamed this wildfire on a lawsuit by the Alliance for the Wild Rockies. The soil burn severity map for the Park Creek fire is below. Ed Regan complained that the wildfire was going to “destroy” the forest and wildlife habitat. Sorry to disappoint you Ed, but it doesn’t look that way!

Meanwhile, when Interior Secretary Ryan Zinke, Ag Secretary Sonny Perdue, Rep Gianforte and Senator Steve Daines toured the Lolo Creek Fire on the Lolo and Bitterroot National Forest – they blamed wildfires on “environmental extremists.” This was despite the fact that there was NEVER ANY lawsuit filed to stop any logging project near the Lolo Peak Fire. Turns out that 66% of the Lolo Peak Fire acres had “unburned” “very low” or “low” soil burn severity, while only 9% had “high.”

More fire severity maps will be posted by the U.S. Forest Service as they become available, so make sure to check back at this link.

Also, two weeks ago I contacted U.S. Forest Service Burned Area Reflectance Classification (BARC) data-producing team to get a satellite-derived data layer of post-fire vegetation condition for Montana wildfires. I was told the U.S. Forest Service no longer releases initial BARC data to the public for “political reasons.” So we will have to patiently wait for that information.

5 Comments

  1. The vegetation severity maps are RAVG products and reflect the % basal area mortality. Sometimes they are a good match with BARC and other times they are not – one example is a crown fire where there is low soil burn severity, but high basal area mortality. And another example is when heat kills the tree crowns, but there is low or moderate soil burn severity. RAVG maps are generally not done until the fire is at least 90% contained, and they like to wait several weeks after that to ensure that any delayed crown mortality is apparent. In Montana in the last few years, the initial RAVG assessment tends to underestimate the mortality, as additional fire-related mortality occurs the following spring.

  2. This would be a great base to start a comparison in soil burn vs morality. Maybe 1, 3, 5 year intervals? It would be good if there was a correlation in bug populations and increased mortality in surrounding stands.

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