The Marshall Fire

The Marshall Fire around Superior and Louisville in Boulder County, Colorado has destroyed more than 580 homes (UPDATE: closer to 1000) already, more than any other fire in Colorado history, despite its relatively moderate 1600 acre scope so far (UPDATE: 6000 acres). Probably 1500 or more people in the metro area are now newly homeless.

The seven worst by the measure of homes destroyed have happened since 2010, and all of the top ten have occurred since 2002. As the article linked above explains:

Officials say the Marshall fire, burning in Boulder County, has burned more than 500 homes, which would make it the most destructive fire in Colorado in terms of the number of homes destroyed.

1. Black Forest fire, Colorado Springs • 2013 — 489 homes
2. Waldo Canyon fire, Colorado Springs • 2012 — 347 homes
3. East Troublesome fire, Grand County • 2020 — 300+ homes
4. High Park fire, Larimer County • 2012 — 259 homes
5. Cameron Peak fire, Walden • 2020 — 224 homes
6. Fourmile Canyon fire, Boulder County • 2010 — 169 homes
7. Spring Creek fire, Costilla and Huerfano counties • 2018 — 141 homes
8. Hayman fire, Lake George • 2002 — 133 homes
9. Iron Mountain fire, Cañon City • 2002 — 106 homes
10. Missionary Ridge fire, Durango • 2002 — 56 homes

Looking at various accounts, so far only 6-9 injuries have resulted from the Marshall Fire, but more than 30,000 people have been forced to evacuate, including at least one or two hospitals. (The high winds caused a building to collapse elsewhere in the metro area injuring six more people.)

This hits close to home. It is about twenty miles away from my home and we are in no danger. But, for example, I have 130 Facebook friends in or near the affected area. At least one of them has lost her home entirely.

The Marshall Fire was still burning largely uncontrolled as of the last news reports of this evening. Snow is in the forecast starting at 11 a.m. today (December 31), and most of New Year's Day. Ebbing winds, snow, and bitter cold conditions forecast for New Year's Day should allow the mostly uncontrolled so far fire to be contained.

Usually, fire season is in hot mid-summer in Colorado. But this wild fire is burning bright on the last two days of December. Hurricane force winds started the originally grass based fire when power lines were brought down. The winds also prevented fire fighters from using aircraft to suppress the fires.

This year had significantly below normal rainfall (not quite 20% below normal), and last year was worse (close to 40% below normal). The last half of the year has been particularly dry. The National Weather Service notes in a tweet that:

One of the many factors that lead to the devastating wildfire today is the recent record dryness. For all periods from Jul 1st to Dec 29th (essentially the second half of the year), Denver has been the driest on record by over an inch. Snowfall is at record low levels, too.

Historical contemporaneously recorded weather records for Denver go back to 1872. We've had just 1.08 inches of precipitation from July 1, 2021 to December 29, 2021 (and no precipitation yesterday either).  

For the most part, rainfall at lower elevations isn't all that important. Most of our critical water supplies come from the mountain snowpack in the South Platte River watershed. 

But dry weather in the foothills and on the plains does create a tinder dry environment prone to extreme wildfires like this one.

More than twenty of Colorado's worst wildfires in the historical record (by any measure) have been recent. There is no reasonable doubt at this point that this record streak of extreme wildfires is mostly driven by global climate change. This is the worst it has been for more than a thousand years in this region, and maybe further back than that. Past bouts of aridity of this scale have destroyed whole civilizations in the historical and prehistoric record repeatedly.