17,325 gardens and a scrapie thingie

by | Dec 16, 2021 | 2021 Wildfire Advent

Firefighters clearing a steep slope down to bare dirt

Photo from InciWeb, Public domain, via Wikimedia Commons 

“What people don’t often realize is that hand crews are kind of the cornerstone … putting in hand lines, that’s essentially the way we stop the fire from growing.”

— Mike Johnson, Assistant Fire Chief, Clark County NV

The basic strategy for fighting a wildfire is to clear a “containment line” around it — a perimeter around the fire that is cleared of anything that can burn to keep the fire from crossing — and let it burn itself out.

Doesn’t sound too bad, does it? Just bring in a bunch of bulldozers and large landclearing equipment, and start clearing.

Not so fast. Wildfires are, well, in the wild. That often means inaccessible areas with steep slopes and no roads. Places where you can’t readily get heavy equipment in.

This is where those hardworking dirt-covered fire crews in heavy clothing and backpacks come in. You know, the ones we see pictures of, swinging wicked-looking firefighting tools. They’re building “hand lines,” sections of the containment line that are carved out by hand and hard work.

This video will show you just how hard it is, what a “scrapie thingie” is, and how coordinated a hand crew is.

To get an idea of what building the hand lines in a large fire means, let’s look at an example.

Guesstimating hand lines in the Caldor fire

Containment map of the Caldor fire 2021-10-13

The 2021 Caldor fire in the Sierra Nevadas burned a total of 221,835 Acres (89,773 hectares). Assuming a rectangular perimeter gives us a minimum containment line of 74 mi (119 km). The map shows where the hand lines are, but it’s really hard to read. So, we’ll guess that they constitute about 10% of the containment line, call it 7 mi (11 km).

The rule of thumb is that a fire line (a section of the containment line) needs to be 1.5 times the height of the surrounding fuel. If we assume that we are in a mostly wooded area with trees and bush to an average height of 30 feet (9 m), our fire lines need to be 45 feet (13.7 m) wide, on average.

7 mi x 45 feet gives us an area of

1,663,200 sq ft (154,516 sq m)

that was cleared by hand crews in the Caldor fire.

To put that in perspective, the median vegetable garden in the United States is 96 sq ft (8.9 sq m). So hand crews cleared the equivalent of

17,325 vegetable gardens!

In 68 days. Working at elevations over 6000 ft (1828 m). Wearing a 45 lb (20.5 kg) backpack. Using Pulaskis, McLeods, and “scrapie thingies”!

 


Share this post to help spread wildfire readiness. Make a donation to help us to do the same.


0 Comments

Submit a Comment

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.